NOTE-WCAG10-HTML-TECHS-20001106
175 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- @@?? we aren't claiming transitional? -->
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta name="generator" content="HTML Tidy, see www.w3.org" />
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>HTML Techniques for Web Content Accessibility Guidelines 1.0</title>
<link rel="stylesheet" type="text/css"
href="http://www.w3.org/StyleSheets/TR/W3C-NOTE" />
<link rel="STYLESHEET" href="style/default.css" type="text/css" />
</head>
<body>
<div class="navbar"><map id="navbar-top" name="navbar-top"
title="Navigation Bar">
<p>[<a href="#toc">contents</a>] [<a href="#html-index">html index</a>]
</p>
<hr class="navbar" title="Navigation area separator" />
</map></div>
<div class="head">
<p><a href="http://www.w3.org/" title="Go to W3C Home Page"><img height="48"
width="72" alt="W3C" src="http://www.w3.org/Icons/w3c_home" /></a></p>
<h1 class="notoc">HTML Techniques for Web Content Accessibility Guidelines
1.0</h1>
<h2 class="notoc">W3C Note 6 November 2000</h2>
<dl>
<dt>This version:</dt>
<dd><a href="http://www.w3.org/TR/2000/NOTE-WCAG10-HTML-TECHS-20001106/">
http://www.w3.org/TR/2000/NOTE-WCAG10-HTML-TECHS-20001106/</a></dd>
<dd>(<a href="html-techniques.txt">plain text</a>, <a
href="html-techniques.ps">PostScript</a>, <a href="html-techniques.pdf">
PDF</a>, <a href="html-techniques.tgz">gzip tar file of HTML</a>, <a
href="html-techniques.zip">zip archive of HTML</a>)</dd>
<dt>Latest version:</dt>
<dd><a href="http://www.w3.org/TR/WCAG10-HTML-TECHS/">
http://www.w3.org/TR/WCAG10-HTML-TECHS/</a> <!--
<DT>Latest public version:
<DD><A HREF="http://www.w3.org/TR/WCAG10-HTML-TECHS/">http://www.w3.org/TR/WCAG10-HTML-TECHS/</A>
--></dd>
<dt>Previous version:</dt>
<dd><a href="http://www.w3.org/TR/2000/NOTE-WCAG10-HTML-TECHS-20000920/">
http://www.w3.org/TR/2000/NOTE-WCAG10-HTML-TECHS-20000920/</a></dd>
<dt>Editors:</dt>
<dd>Wendy Chisholm, <a href="http://www.w3.org/">W3C</a>;<br />
Gregg Vanderheiden, <a href="http://www.tracecenter.org/">Trace R & D
Center</a> University of Wisconsin -- Madison;<br />
Ian Jacobs, <a href="http://www.w3.org/">W3C</a></dd>
</dl>
<p class="copyright"><a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
©1999 - 2000 <a href="http://www.w3.org/"><abbr
title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a
href="http://www.lcs.mit.edu/"><abbr
title="Massachusetts Institute of Technology">MIT</abbr></a>, <a
href="http://www.inria.fr/"><abbr lang="fr"
title="Institut National de Recherche en Informatique et Automatique">
INRIA</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights
Reserved. W3C <a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">
liability</a>, <a
href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">
trademark</a>, <a
href="http://www.w3.org/Consortium/Legal/copyright-documents-19990405">document
use</a> and <a
href="http://www.w3.org/Consortium/Legal/copyright-software-19980720">software
licensing</a> rules apply.</p>
</div>
<hr />
<h2 class="nonb"><a id="Abstract" name="Abstract">Abstract</a></h2>
<p>This document describes techniques for authoring accessible Hypertext Markup
Language (<acronym title="Hypertext Markup Language">HTML</acronym>) content
(refer to HTML 4.01 <cite><a href="#ref-HTML4" title="Link to reference HTML4">
[HTML4]</a></cite>). This document is intended to help authors of Web content
who wish to claim conformance to "Web Content Accessibility Guidelines 1.0"
(<cite><a href="#ref-WCAG10"
title="Link to reference WCAG10">[WCAG10]</a></cite>). While the techniques in
this document should help people author HTML that conforms to "Web Content
Accessibility Guidelines 1.0", these techniques are neither guarantees of
conformance nor the only way an author might produce conforming content.</p>
<p>This document is part of a series of documents about techniques for
authoring accessible Web content. For information about the other documents in
the series, please refer to "Techniques for Web Content Accessibility
Guidelines 1.0" <cite><a href="#ref-WCAG10-TECHS"
title="Link to reference WCAG10-TECHS">[WCAG10-TECHS]</a></cite>.</p>
<p><strong>Note:</strong> This document contains a number of examples that
illustrate accessible solutions in CSS but also deprecated examples that
illustrate what content developers should not do. The deprecated examples are
highlighted and readers should approach them with caution -- they are meant for
illustrative purposes only.</p>
<h2 class="nonb"><a id="Status" name="Status">Status of this document</a></h2>
<p>This version has been published to correct some broken links in the previous
version.</p>
<p>The 6 November 2000 version of this document is a Note in a series of Notes
produced and endorsed by the <a href="http://www.w3.org/WAI/GL/">Web Content
Accessibility Guidelines Working Group</a> (WCAG WG). This Note has not been
reviewed or endorsed by W3C Members. The series of documents supersedes the
single document <a
href="http://www.w3.org/TR/1999/WAI-WEBCONTENT-TECHS-19990505/">5 May 1999 W3C
Note Techniques for Web Content Accessibility Guidelines 1.0</a>. The topics
from the earlier document have been separated into technology-specific
documents that may evolve independently. Smaller technology-specific documents
allow authors to focus on a particular technology.</p>
<p>While the "Web Content Accessibility Guidelines 1.0" Recommendation <cite><a
href="#ref-WCAG10" title="Link to reference WCAG10">[WCAG10]</a></cite> is a
stable document, this series of companion documents is expected to evolve as
technologies change and content developers discover more effective techniques
for designing accessible Web content.</p>
<p>The <a href="http://www.w3.org/WAI/GL/wai-gl-techniques-changes.html">
history of changes to the series of documents</a> as well as the <a
href="http://www.w3.org/WAI/GL/wai-gl-tech-issues.html">list of open and closed
issues</a> are available. Readers are encouraged to comment on the document and
propose resolutions to current issues. Please send detailed comments on this
document to the Working Group at <a href="mailto:w3c-wai-gl@w3.org">
w3c-wai-gl@w3.org</a>; <a
href="http://lists.w3.org/Archives/Public/w3c-wai-gl/">public archives</a> are
available.</p>
<p>The English version of this specification is the only normative version. <a
href="http://www.w3.org/WAI/GL/WAI-WEBCONTENT-TRANSLATIONS">Translations of
this document</a> may be available.</p>
<p>The list of known errors in this document is available at <a
href="http://www.w3.org/WAI/GL/WAI-WEBCONTENT-ERRATA">"Errata in Web Content
Accessibility Guidelines</a>." Please report errors in this document to <a
href="mailto:wai-wcag-editor@w3.org">wai-wcag-editor@w3.org</a>.</p>
<p>The <a href="http://www.w3.org/WAI/">Web Accessibility Initiative (<acronym
title="Web Accessibility Initiative">WAI</acronym>)</a> of the World Wide Web
Consortium (<acronym>W3C</acronym>) makes available a variety of resources on
Web accessibility. WAI Accessibility Guidelines are produced as part of the <a
href="http://www.w3.org/WAI/Technical/Activity">WAI Technical Activity</a>. The
goals of the Web Content Accessibility Guidelines Working Group are described
in <a href="http://www.w3.org/WAI/GL/new-charter-2000.html">the
charter</a>.</p>
<p>A list of <a href="http://www.w3.org/TR/">current W3C Recommendations and
other technical documents</a> is available.</p>
<!--NewPage--><!-- this is for html2ps -->
<div class="toc">
<h2 class="notoc"><a id="toc" name="toc">Table of Contents</a></h2>
<ul class="toc">
<li class="tocline2"><a id="toc-Abstract" href="#Abstract" name="toc-Abstract"
class="tocxref">Abstract</a></li>
<li class="tocline2"><a id="toc-Status" href="#Status" name="toc-Status"
class="tocxref">Status of this document</a></li>
<li class="tocline2"><a id="toc-document" href="#document" name="toc-document"
class="tocxref">1 Document structure and metadata</a>
<ul class="toc">
<li class="tocline3"><a id="toc-document-meta" href="#document-meta"
name="toc-document-meta" class="tocxref">1.1 Metadata</a></li>
<li class="tocline3"><a id="toc-grouping" href="#grouping" name="toc-grouping"
class="tocxref">1.2 Structural grouping</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-language" href="#language" name="toc-language"
class="tocxref">2 Language information</a>
<ul class="toc">
<li class="tocline3"><a id="toc-changes-in-lang" href="#changes-in-lang"
name="toc-changes-in-lang" class="tocxref">2.1 Identifying changes in
language</a></li>
<li class="tocline3"><a id="toc-identify-primary-lang"
href="#identify-primary-lang" name="toc-identify-primary-lang" class="tocxref">
2.2 Identifying the primary language</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-text" href="#text" name="toc-text"
class="tocxref">3 Text markup</a>
<ul class="toc">
<li class="tocline3"><a id="toc-text-emphasis" href="#text-emphasis"
name="toc-text-emphasis" class="tocxref">3.1 Emphasis</a></li>
<li class="tocline3"><a id="toc-text-abbr" href="#text-abbr"
name="toc-text-abbr" class="tocxref">3.2 Acronyms and abbreviations</a></li>
<li class="tocline3"><a id="toc-text-quotes" href="#text-quotes"
name="toc-text-quotes" class="tocxref">3.3 Quotations</a></li>
<li class="tocline3"><a id="toc-text-markup" href="#text-markup"
name="toc-text-markup" class="tocxref">3.4 Markup and style sheets rather than
images: The example of math</a></li>
<li class="tocline3"><a id="toc-misc-markup" href="#misc-markup"
name="toc-misc-markup" class="tocxref">3.5 Eight other structural elements (to
identify citations, code fragments, deleted text, and others)</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-lists" href="#lists" name="toc-lists"
class="tocxref">4 Lists</a>
<ul class="toc">
<li class="tocline3"><a id="toc-list-bullets" href="#list-bullets"
name="toc-list-bullets" class="tocxref">4.1 Use style sheets to change list
bullets</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-tables" href="#tables" name="toc-tables"
class="tocxref">5 Tables</a>
<ul class="toc">
<li class="tocline3"><a id="toc-data-tables" href="#data-tables"
name="toc-data-tables" class="tocxref">5.1 Tables of data</a></li>
<li class="tocline3"><a id="toc-tables-layout" href="#tables-layout"
name="toc-tables-layout" class="tocxref">5.2 Tables for layout</a></li>
<li class="tocline3"><a id="toc-wrapped-text" href="#wrapped-text"
name="toc-wrapped-text" class="tocxref">5.3 Linearizing tables</a></li>
<li class="tocline3"><a id="toc-bc-tables" href="#bc-tables"
name="toc-bc-tables" class="tocxref">5.4 Backward compatibility issues for
tables</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-links" href="#links" name="toc-links"
class="tocxref">6 Links</a>
<ul class="toc">
<li class="tocline3"><a id="toc-link-text" href="#link-text"
name="toc-link-text" class="tocxref">6.1 Link text</a></li>
<li class="tocline3"><a id="toc-group-bypass" href="#group-bypass"
name="toc-group-bypass" class="tocxref">6.2 Grouping and bypassing
links</a></li>
<li class="tocline3"><a id="toc-link-accesskey" href="#link-accesskey"
name="toc-link-accesskey" class="tocxref">6.3 Keyboard access</a></li>
<li class="tocline3"><a id="toc-anchors-targets" href="#anchors-targets"
name="toc-anchors-targets" class="tocxref">6.4 Anchors and targets</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-images" href="#images" name="toc-images"
class="tocxref">7 Images and image maps</a>
<ul class="toc">
<li class="tocline3"><a id="toc-image-text-equivalent"
href="#image-text-equivalent" name="toc-image-text-equivalent" class="tocxref">
7.1 Short text equivalents for images ("alt-text")</a></li>
<li class="tocline3"><a id="toc-long-descriptions" href="#long-descriptions"
name="toc-long-descriptions" class="tocxref">7.2 Long descriptions of
images</a></li>
<li class="tocline3"><a id="toc-ascii-art" href="#ascii-art"
name="toc-ascii-art" class="tocxref">7.3 Ascii art</a></li>
<li class="tocline3"><a id="toc-image-maps" href="#image-maps"
name="toc-image-maps" class="tocxref">7.4 Image maps</a></li>
<li class="tocline3"><a id="toc-color-images" href="#color-images"
name="toc-color-images" class="tocxref">7.5 Color in images</a></li>
<li class="tocline3"><a id="toc-animated-images" href="#animated-images"
name="toc-animated-images" class="tocxref">7.6 Animated images</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-objects" href="#objects" name="toc-objects"
class="tocxref">8 Applets and other programmatic objects</a>
<ul class="toc">
<li class="tocline3"><a id="toc-applet-text-equivalent"
href="#applet-text-equivalent" name="toc-applet-text-equivalent"
class="tocxref">8.1 Text and non-text equivalents for applets and programmatic
objects</a></li>
<li class="tocline3"><a id="toc-accessible-applets" href="#accessible-applets"
name="toc-accessible-applets" class="tocxref">8.2 Directly accessible
applets</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-audio-and-video" href="#audio-and-video"
name="toc-audio-and-video" class="tocxref">9 Audio and video</a>
<ul class="toc">
<li class="tocline3"><a id="toc-audio-information" href="#audio-information"
name="toc-audio-information" class="tocxref">9.1 Audio information</a></li>
<li class="tocline3"><a id="toc-text-equivs-multimedia"
href="#text-equivs-multimedia" name="toc-text-equivs-multimedia"
class="tocxref">9.2 Text equivalents for multimedia</a></li>
<li class="tocline3"><a id="toc-embed-multimedia" href="#embed-multimedia"
name="toc-embed-multimedia" class="tocxref">9.3 Embedding multimedia
objects</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-frames" href="#frames" name="toc-frames"
class="tocxref">10 Frames</a>
<ul class="toc">
<li class="tocline3"><a id="toc-frame-names" href="#frame-names"
name="toc-frame-names" class="tocxref">10.1 Providing a frame title</a></li>
<li class="tocline3"><a id="toc-frame-text-equivalent"
href="#frame-text-equivalent" name="toc-frame-text-equivalent" class="tocxref">
10.2 Describing frame relationships</a></li>
<li class="tocline3"><a id="toc-noframes" href="#noframes" name="toc-noframes"
class="tocxref">10.3 Writing for browsers that do not support FRAME</a></li>
<li class="tocline3"><a id="toc-frame-has-html-src" href="#frame-has-html-src"
name="toc-frame-has-html-src" class="tocxref">10.4 Frame sources</a></li>
<li class="tocline3"><a id="toc-no-new-windows" href="#no-new-windows"
name="toc-no-new-windows" class="tocxref">10.5 Using FRAME targets</a></li>
<li class="tocline3"><a id="toc-alt-frames" href="#alt-frames"
name="toc-alt-frames" class="tocxref">10.6 Alternatives to frames</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-forms" href="#forms" name="toc-forms"
class="tocxref">11 Forms</a>
<ul class="toc">
<li class="tocline3"><a id="toc-forms-keyboard-access"
href="#forms-keyboard-access" name="toc-forms-keyboard-access" class="tocxref">
11.1 Keyboard access to forms</a></li>
<li class="tocline3"><a id="toc-forms-grouping" href="#forms-grouping"
name="toc-forms-grouping" class="tocxref">11.2 Grouping form controls</a></li>
<li class="tocline3"><a id="toc-forms-labels" href="#forms-labels"
name="toc-forms-labels" class="tocxref">11.3 Labeling form controls</a></li>
<li class="tocline3"><a id="toc-forms-graphical-buttons"
href="#forms-graphical-buttons" name="toc-forms-graphical-buttons"
class="tocxref">11.4 Graphical buttons</a></li>
<li class="tocline3"><a id="toc-forms-specific" href="#forms-specific"
name="toc-forms-specific" class="tocxref">11.5 Techniques for specific
controls</a></li>
<li class="tocline3"><a id="toc-bc-forms" href="#bc-forms" name="toc-bc-forms"
class="tocxref">11.6 Backward compatibility issues for forms</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-scripts" href="#scripts" name="toc-scripts"
class="tocxref">12 Scripts</a>
<ul class="toc">
<li class="tocline3"><a id="toc-scripts-gt" href="#scripts-gt"
name="toc-scripts-gt" class="tocxref">12.1 Graceful transformation of
scripts</a></li>
<li class="tocline3"><a id="toc-scripts-flicker" href="#scripts-flicker"
name="toc-scripts-flicker" class="tocxref">12.2 Scripts that cause
flickering</a></li>
<li class="tocline3"><a id="toc-scripts-movement-blinking"
href="#scripts-movement-blinking" name="toc-scripts-movement-blinking"
class="tocxref">12.3 Scripts that cause movement and blinking</a></li>
<li class="tocline3"><a id="toc-directly-accessible-scripts"
href="#directly-accessible-scripts" name="toc-directly-accessible-scripts"
class="tocxref">12.4 Directly accessible scripts</a></li>
<li class="tocline3"><a id="toc-scripts-alt" href="#scripts-alt"
name="toc-scripts-alt" class="tocxref">12.5 Alternative presentation of
scripts</a></li>
<li class="tocline3"><a id="toc-script-refresh" href="#script-refresh"
name="toc-script-refresh" class="tocxref">12.6 Page updates and new
windows</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-html-index" href="#html-index"
name="toc-html-index" class="tocxref">13 Index of HTML elements and
attributes</a>
<ul class="toc">
<li class="tocline3"><a id="toc-index-elements" href="#index-elements"
name="toc-index-elements" class="tocxref">Elements</a></li>
<li class="tocline3"><a id="toc-index-attributes" href="#index-attributes"
name="toc-index-attributes" class="tocxref">Attributes</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-References" href="#References"
name="toc-References" class="tocxref">14 References</a></li>
<li class="tocline2"><a id="toc-Resources" href="#Resources"
name="toc-Resources" class="tocxref">15 Resources</a>
<ul class="toc">
<li class="tocline3"><a id="toc-OtherGuidelines" href="#OtherGuidelines"
name="toc-OtherGuidelines" class="tocxref">15.1 Other guidelines</a></li>
<li class="tocline3"><a id="toc-ToolResources" href="#ToolResources"
name="toc-ToolResources" class="tocxref">15.2 User agents and other
tools</a></li>
<li class="tocline3"><a id="toc-AccessResources" href="#AccessResources"
name="toc-AccessResources" class="tocxref">15.3 Accessibility
resources</a></li>
</ul>
</li>
<li class="tocline2"><a id="toc-Acknowledgments" href="#Acknowledgments"
name="toc-Acknowledgments" class="tocxref">16 Acknowledgments</a></li>
</ul>
</div>
<div class="noprint">
<hr title="Separator from Introduction" />
</div>
<!--NewPage--><!-- this is for html2ps -->
<h2>1 <a id="document" name="document">Document structure and metadata</a></h2>
<p>Content developers should use structural markup and use it according to
specification. Structural elements and attribute (refer to the <a
href="#html-index">index of HTML elements and attributes</a> to identify them)
promote consistency in documents and supply information to other tools (e.g.,
indexing tools, search engines, programs that extract tables to databases,
navigation tools that use heading elements, and automatic translation software
that translates text from one language into another.</p>
<h3>1.1 <a id="document-meta" name="document-meta">Metadata</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-use-metadata"
class="noxref">13.2</a> Provide metadata to add semantic information to pages
and sites. [Priority 2]</li>
</ul>
<p>Some structural elements provide information about the document itself. This
is called "metadata" about the document -- metadata is information about data.
Well-crafted metadata can provide important orientation information to users.
HTML elements that provide useful information about a document include:</p>
<h4>1.1.1 <a id="doc-title" name="doc-title">TITLE: The document
title.</a></h4>
<p>Note that the (mandatory) TITLE element, which only appears once in a
document, is different from the "<a href="#adef-title">title</a>" attribute,
which applies to almost every HTML 4.01 element. Content developers should use
the "title" attribute in accordance with the HTML 4.01 specification. For
example, "title" should be used with links to provide information about the
target of the link.</p>
<h4>1.1.2 <a id="title-element" name="title-element">The</a> <a
href="#edef-ADDRESS">ADDRESS</a> element</h4>
<p>This element can be used to provide information about the creator of the
page.</p>
<h4>1.1.3 <a id="meta-element" name="meta-element">The</a> <a
href="#edef-META">META</a> element</h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-no-periodic-refresh"
class="noxref">7.4</a> Until user agents provide the ability to stop the
refresh, do not create periodically auto-refreshing pages. [Priority 2]
,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-no-auto-forward"
class="noxref">7.5</a> Until user agents provide the ability to stop
auto-redirect, do not use markup to redirect pages automatically. Instead,
configure the server to perform redirects. [Priority 2] .</li>
</ul>
<p>This element can specify metadata for a document including keywords, and
information about the author. Please refer to the section on <a
href="http://www.w3.org/TR/WCAG10-CORE-TECHS/#auto-page-refresh">automatic page
refresh</a> for information on why META should <strong>not</strong> be used to
redirect or auto-refresh pages.</p>
<p>The following are <strong>deprecated</strong> HTML examples. The first
changes the user's page at page at regular intervals. Content developers should
<strong>not</strong> use this technique to simulate "push" technology.
Developers cannot predict how much time a user will require to read a page;
premature refresh can disorient users. Content developers should avoid periodic
refresh and allow users to choose when they want the latest information.</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<META http-equiv="refresh" content="60">
<BODY>
<P><em>...Information...</em>
</BODY>
</pre>
<p class="off">End example.</p>
</div>
<p>The following HTML example (using the META element) forwards the user from
one page to another after a timeout. However, users should <strong>not</strong>
redirect users with this markup since is non-standard, it disorients users, and
it can disrupt a browser's history of visited pages.</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<HEAD>
<TITLE>Don't use this!</TITLE>
<META http-equiv="refresh" content="5;
http://www.example.com/newpage">
</HEAD>
<BODY>
<P>If your browser supports Refresh,
you'll be transported to our
<A href="http://www.example.com/newpage">new site</A>
in 5 seconds, otherwise, select the link manually.
</BODY>
</pre>
<p class="off">End example.</p>
</div>
<h4>1.1.4 <a id="doctype" name="doctype">The !DOCTYPE statement</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-identify-grammar"
class="noxref">3.2</a> Create documents that validate to published formal
grammars. [Priority 2]</li>
</ul>
<p>Validating to a published formal grammar and declaring that validation at
the beginning of a document lets the user know that the structure of the
document is sound. It also lets the user agent know where to look for semantics
if it needs to. <a href="http://validator.w3.org/">The W3C Validation
Service</a> validates documents against a <a
href="http://validator.w3.org/sgml-lib/catalog">whole list of published
grammars</a>.</p>
<p>It is preferable to validate to W3C grammars. Refer to the <a
href="http://www.w3.org/TR/WCAG10-CORE-TECHS/#access-reviewed">Technologies
Reviewed for Accessibility</a>.</p>
<!-- <p>We will link to XML techniques document when ready.</p> -->
<h4>1.1.5 The <a id="link-metadata" name="link-metadata" href="#edef-LINK">
LINK</a> element and navigation tools</h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-bundled-version"
class="noxref">13.9</a> Provide information about document collections (i.e.,
documents comprising multiple pages.). [Priority 3]</li>
</ul>
<p>Content developers should use the <a href="#edef-LINK">LINK</a> element and
link types (refer to <cite><a href="#ref-HTML4"
title="Link to reference HTML4">[HTML4]</a></cite>, section 6.12) to describe
document navigation mechanisms and organization. Some user agents may
synthesize navigation tools or allow ordered printing of a set of documents
based on such markup.</p>
<div class="example">
<p><strong><a id="example-link" name="example-link">Example.</a></strong></p>
<p>The following <a href="#edef-LINK">LINK</a> elements might be included in
the head of chapter 2 of a book:</p>
<pre>
<LINK rel="Next" href="chapter3">
<LINK rel="Prev" href="chapter1">
<LINK rel="Start" href="cover">
<LINK rel="Glossary" href="glossary">
</pre>
<p class="off">End example.</p>
</div>
<h4>1.1.6 The <a id="link-alternative-docs" name="link-alternative-docs"
href="#edef-LINK">LINK</a> element and alternative documents</h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-fallback-page"
class="noxref">6.5</a> Ensure that dynamic content is accessible or provide an
alternative presentation or page. [Priority 2]</li>
</ul>
<p>The LINK element may also be used to designate alternative documents.
Browsers should load the alternative page automatically based on the user's
browser type and preferences. For example, use the LINK element as follows:</p>
<div class="example">
<p><strong>Example.</strong></p>
<p>User agents that support LINK will load the alternative page for those users
whose browsers may be identified as supporting "aural","braille", or "tty"
rendering.</p>
<pre>
<HEAD>
<TITLE>Welcome to the Virtual Mall!</TITLE>
<LINK title="Text-only version"
rel="alternate"
href="text_only"
media="aural, braille, tty">
</HEAD>
<BODY><P>...</BODY>
</pre>
<p class="off">End example.</p>
</div>
<h3>1.2 <a id="grouping" name="grouping">Structural grouping</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-group-information"
class="noxref">12.3</a> Divide large blocks of information into more manageable
groups where natural and appropriate. [Priority 2]</li>
</ul>
<p>The following HTML 4.01 mechanisms group content and make it easier to
understand.:</p>
<ul>
<li>Use <a href="#edef-FIELDSET">FIELDSET</a> to <a href="#forms">group form
controls into semantic units</a> and describe the group with the <a
href="#edef-LEGEND">LEGEND</a> element.</li>
<li>Use <a href="#edef-OPTGROUP">OPTGROUP</a> to <a
href="#forms-group-options">organize long lists of menu options into smaller
groups.</a>.</li>
<li><a href="#tables">Use tables for tabular data</a> and describe the table
with <a href="#edef-CAPTION">CAPTION</a>.</li>
<li><a href="#tables">Group table rows and columns</a> with <a
href="#edef-THEAD">THEAD</a>, <a href="#edef-TBODY">TBODY</a>, <a
href="#edef-TFOOT">TFOOT</a>, and <a href="#edef-COLGROUP">COLGROUP</a>.</li>
<li><a href="#lists">Nest lists</a> with <a href="#edef-UL">UL</a>, <a
href="#edef-OL">OL</a>, and <a href="#edef-DL">DL</a>.</li>
<li>Use section headings (<a href="#edef-H1">H1</a> - H6) to create structured
documents and break up long stretches of text. Refer to the following section
for more information.</li>
<li>Break up lines of text into paragraphs (with the <a href="#edef-P">P</a>
element).</li>
<li>Group related links. Refer to the section <a href="#group-bypass">Grouping
and bypassing links</a></li>
</ul>
<p>All of these grouping mechanisms should be used when appropriate and
natural, i.e., when the information lends itself to logical groups. Content
developers should not create groups randomly, as this will confuse all users.
<!--Link to style section for no spaces in titles ??? --></p>
<h4>1.2.1 <a id="document-headers" name="document-headers">Section
headings</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-logical-headings"
class="noxref">3.5</a> Use header elements to convey document structure and use
them according to specification. [Priority 2]</li>
</ul>
<p>Long documents are often divided into a variety of chapters, chapters have
subtopics and subtopics are divided into various sections, sections into
paragraphs, etc. These semantic chunks of information make up the structure of
the document.</p>
<p>Sections should be introduced with the HTML heading elements (<a
href="#edef-H1">H1</a>-H6). Other markup may complement these elements to
improve presentation (e.g., the <a href="#edef-HR">HR</a> element to create a
horizontal dividing line), but visual presentation is not sufficient to
identify document sections.</p>
<p>Since some users skim through a document by navigating its headings, it is
important to use them appropriately to convey document structure. Users should
order heading elements properly. For example, in HTML, H2 elements should
follow H1 elements, H3 elements should follow H2 elements, etc. Content
developers should not "skip" levels (e.g., H1 directly to H3). Do not use
headings to create font effects; use <a
href="http://www.w3.org/TR/WCAG10-CSS-TECHS/#style-fonts">style sheets to
change font styles</a> for example.</p>
<p>Note that in HTML, heading elements (H1 - H6) only start sections, they
don't contain them as element content. The following HTML markup shows how
style sheets may be used to control the appearance of a heading and the content
that follows:</p>
<div class="example">
<p><strong><a id="example-header" name="example-header">
Example.</a></strong></p>
<pre>
<HEAD>
<TITLE>Cooking techniques</TITLE>
<STYLE type="text/css">
/* Indent heading and following content */
DIV.section2 { margin-left: 5% }
</STYLE>
</HEAD>
<BODY>
<H1>Cooking techniques</H1>
<em>... some text here ...</em>
<DIV class="section2">
<H2>Cooking with oil</H2>
<em>... text of the section ...</em>
</DIV>
<DIV class="section2">
<H2>Cooking with butter</H2>
<em>... text of the section ...</em>
</DIV>
</pre>
<p class="off">End example.</p>
</div>
<p><a href="#links">See also the section on links</a>.</p>
<h2>2 <a id="language" name="language">Language information</a></h2>
<h3>2.1 <a id="changes-in-lang" name="changes-in-lang">Identifying changes in
language</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-identify-changes"
class="noxref">4.1</a> Clearly identify changes in the natural language of a
document's text and any text equivalents (e.g., captions).
[Priority 1]</li>
</ul>
<p>If you use a number of different languages on a page, make sure that any
changes in language are clearly identified by using the "<a
href="#adef-lang">lang</a>" attribute:</p>
<div class="example">
<p><strong><a id="example-lang" name="example-lang">Example.</a></strong></p>
<pre>
<P>And with a certain <SPAN lang="fr">je ne sais quoi</SPAN>,
she entered both the room, and his life, forever. <Q>My name
is Natasha,</Q> she said. <Q lang="it">Piacere,</Q>
he replied in impeccable Italian, locking the door.
</pre>
<p class="off">End example.</p>
</div>
<p>Identifying changes in language are important for a number of reasons:</p>
<ol>
<li>Users who are reading the document in braille will be able to substitute
the appropriate control codes (markup) where language changes occur to ensure
that the braille translation software will generate the correct characters
(accented characters, for instance). These control codes also prevent braille
contractions from being generated, which could further confuse the user.
Braille contractions combine commonly used groups of characters that usually
appear in multiple cells into a single cell. For example, "ing" which usually
takes up three cells (one for each character) can be contracted into a single
cell.</li>
<li>Similarly, speech synthesizers that "speak" multiple languages will be able
to generate the text in the appropriate accent with proper pronunciation. If
changes are not marked, the synthesizer will try its best to speak the words in
the primary language it works in. Thus, the French word for car, <span
lang="fr">"voiture"</span> would be pronounced "voter" by a speech synthesizer
that uses English as its primary language.</li>
<li>Users who are unable to translate between languages themselves, will be
able to have unfamiliar languages translated by machine translators.</li>
</ol>
<h3>2.2 <a id="identify-primary-lang" name="identify-primary-lang">Identifying
the primary language</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-identify-lang"
class="noxref">4.3</a> Identify the primary natural language of a document.
[Priority 3]</li>
</ul>
<p>It is also good practice to identify the primary language of a document,
either with markup (as shown below) or through HTTP headers.</p>
<div class="example">
<p><strong><a id="example-lang-2" name="example-lang-2">
Example.</a></strong></p>
<pre>
<HTML lang="fr">
....rest of an HTML document written in French...
</HTML>
</pre>
<p class="off">End example.</p>
</div>
<h2>3 <a id="text" name="text">Text markup</a></h2>
<p>The following sections discuss ways to add structure to pieces of text.</p>
<h3>3.1 <a id="text-emphasis" name="text-emphasis">Emphasis</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-style-sheets"
class="noxref">3.3</a> Use style sheets to control layout and presentation.
[Priority 2]</li>
</ul>
<p>The proper HTML elements should be used to mark up emphasis: <a
href="#edef-EM">EM</a> and <a href="#edef-STRONG">STRONG</a>. The <a
href="#edef-B">B</a> and <a href="#edef-I">I</a> elements should not be used;
they are used to create a visual presentation effect. The EM and STRONG
elements were designed to indicate structural emphasis that may be rendered in
a variety of ways (font style changes, speech inflection changes, etc.)
<!--Could add a
section for SUB/SUP saying don't use for small text --></p>
<h3>3.2 <a id="text-abbr" name="text-abbr">Acronyms and abbreviations</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-expand-abbr"
class="noxref">4.2</a> Specify the expansion of each abbreviation or acronym in
a document where it first occurs. [Priority 3]</li>
</ul>
<p>Mark up abbreviations and acronyms with <a href="#edef-ABBR">ABBR</a> and <a
href="#edef-ACRONYM">ACRONYM</a> and use "<a href="#adef-title">title</a>" to
indicate the expansion:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<P>Welcome to the <ACRONYM title="World Wide Web">WWW</ACRONYM>!
</pre>
<p class="off">End example.</p>
</div>
<p>This also applies to shortened phrases used as headings for table row or
columns. If a heading is already abbreviated provide the expansion in ABBR. If
a heading is long, you may wish to provide an abbreviation, as described in <a
href="#data-tables">Data Tables</a>.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
...
<TH>First name</TH>
<TH><ABBR title="Social Security Number">SS#</ABBR>
...
</pre>
<p class="off">End example.</p>
</div>
<h3>3.3 <a id="text-quotes" name="text-quotes">Quotations</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-quotes" class="noxref">
3.7</a> Mark up quotations. Do not use quotation markup for formatting effects
such as indentation. [Priority 2]</li>
</ul>
<p>The <a href="#edef-Q">Q</a> and <a href="#edef-BLOCKQUOTE">BLOCKQUOTE</a>
elements mark up inline and block quotations, respectively.</p>
<div class="example">
<p><strong>Example.</strong></p>
<p>This example marks up a longer quotation with <a href="#edef-BLOCKQUOTE">
BLOCKQUOTE</a>:</p>
<pre>
<BLOCKQUOTE cite="http://www.example.com/loveslabourlost">
<P>Remuneration! O! that's the Latin word for three farthings.
--- William Shakespeare (Love's Labor Lost).
</P>
</BLOCKQUOTE>
</pre>
<p class="off">End example.</p>
</div>
<h3>3.4 <a id="text-markup" name="text-markup">Markup and style sheets rather
than images: The example of math</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-use-markup"
class="noxref">3.1</a> When an appropriate markup language exists, use markup
rather than images to convey information. [Priority 2]</li>
</ul>
<p>Using markup (and style sheets) where possible rather than images (e.g., a
mathematical equation) promotes accessibility for the following reasons:</p>
<ul>
<li>Text may be magnified or interpreted as speech or braille.</li>
<li>Search engines can use text information.</li>
</ul>
<p>As an example, consider these techniques for putting mathematics on the
Web:</p>
<ul>
<li>Ensure that users know what variables represent, for example, in the
equation "F = m * a", indicate that F= Force, m = mass, a = acceleration.</li>
<li>For straightforward equations, use characters, as in "x + y = z"</li>
<li>For more complex equations, mark them up with MathML (<cite><a
href="#ref-MATHML" title="Link to reference MATHML">[MATHML]</a></cite>) or
TeX. <strong>Note.</strong> MathML can be used to create very accessible
documents but currently is not as widely supported or used as TeX.</li>
<li>Provide a text description of the equation and, where possible, use
character entity references to create the mathematical symbols. A text
equivalent must be provided if the equation is represented by one or more
images.</li>
</ul>
<p>TeX is commonly used to create technical papers which are then converted to
HTML for publication on the Web. However, converters tend to generate images,
use deprecated markup, and use tables for layout. Consequently, content
providers should:</p>
<ol>
<li>Make the original TeX (or LaTeX) document available on the Web. There is a
system called "AsTeR" (<cite><a href="#ref-ASTER"
title="Link to reference ASTER">[ASTER]</a></cite>) that can create an auditory
rendition of TeX and LaTeX documents. Also, IBM has a plug-in for Netscape and
Internet Explorer that reads TeX/LaTeX documents and some of MathML (refer to
<cite><a href="#ref-HYPERMEDIA" title="Link to reference HYPERMEDIA">
[HYPERMEDIA]</a></cite>). <strong>Note.</strong> These tools work primarily in
the English environment and may not work so well with speech synthesizers whose
primary language is not English.</li>
<li>Ensure that the HTML created by the conversion process is accessible.
Provide a single description of the equation (rather than "alt" text on every
generated image as there may be small images for bits and pieces of the
equation).</li>
</ol>
<h3>3.5 <a id="misc-markup" name="misc-markup">Eight other structural elements
(to identify citations, code fragments, deleted text, and others)</a></h3>
<p>The HTML 4.01 specification defines the following structural elements for
miscellaneous markup needs:</p>
<dl>
<dt><a href="#edef-CITE">CITE</a></dt>
<dd>Contains a citation or a reference to other sources.</dd>
<dt><a href="#edef-DFN">DFN</a></dt>
<dd>Indicates that this is the defining instance of the enclosed term.</dd>
<dt><a href="#edef-CODE">CODE</a></dt>
<dd>Designates a fragment of computer code.</dd>
<dt><a href="#edef-SAMP">SAMP</a></dt>
<dd>Designates sample output from programs, scripts, etc.</dd>
<dt><a href="#edef-KBD">KBD</a></dt>
<dd>Indicates text to be entered by the user.</dd>
<dt><a href="#edef-VAR">VAR</a></dt>
<dd>Indicates an instance of a variable or program argument.</dd>
<dt><a href="#edef-INS">INS</a></dt>
<dd>Indicates text inserted into a document.</dd>
<dt><a href="#edef-DEL">DEL</a></dt>
<dd>Indicates text deleted from a document.</dd>
</dl>
<h2>4 <a id="lists" name="lists">Lists</a></h2>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-list-structure"
class="noxref">3.6</a> Mark up lists and list items properly.
[Priority 2]</li>
</ul>
<p>The HTML list elements <a href="#edef-DL">DL</a>, <a href="#edef-UL">UL</a>,
and <a href="#edef-OL">OL</a> should only be used to create lists, not for
formatting effects such as indentation. Refer to information on <a
href="http://www.w3.org/TR/WCAG10-CSS-TECHS/#style-alignment">CSS and tables
for layout</a> in the CSS Techniques <cite><a href="#ref-WCAG10-CSS-TECHNIQUES"
title="Link to reference WCAG10-CSS-TECHNIQUES">
[WCAG10-CSS-TECHNIQUES]</a></cite>.</p>
<!-- There used to be a technique here. Is it gone? -IJ -->
<p><a id="order-lists" name="order-lists">Ordered lists help non-visual users
navigate.</a> Non-visual users may "get lost" in lists, especially in nested
lists and those that do not indicate the specific nest level for each list
item. Until user agents provide a means to identify list context clearly (e.g.,
by supporting the ':before' pseudo-element in CSS2), content developers should
include contextual clues in their lists.</p>
<p>For numbered lists, compound numbers are more informative than simple
numbers. Thus, a list numbered "1, 1.1, 1.2, 1.2.1, 1.3, 2, 2.1," provides more
context than the same list without compound numbers, which might be formatted
as follows:</p>
<pre>
1.
1.
2.
1.
3.
2.
1.
</pre>
<p>and would be spoken as "1, 1, 2, 1, 2, 3, 2, 1", conveying no information
about list depth.</p>
<p><cite><a href="#ref-CSS1" title="Link to reference CSS1">[CSS1]</a></cite>
and <cite><a href="#ref-CSS2" title="Link to reference CSS2">[CSS2]</a></cite>
allow users to control number styles (for all lists, not just ordered) through
user style sheets.</p>
<div class="css-example">
<p><strong>Example.</strong></p>
<p>The following CSS2 style sheet shows how to specify compound numbers for
nested lists created with either UL or OL elements. Items are numbered as "1",
"1.1", "1.1.1", etc.</p>
<pre>
<STYLE type="text/css">
UL, OL { counter-reset: item }
LI { display: block }
LI:before { content: counters(item, "."); counter-increment: item }
</STYLE>
</pre>
<p class="off">End example.</p>
</div>
<p>Until either CSS2 is widely supported or user agents allow users to control
rendering of lists through other means, authors should consider providing
contextual clues in unnumbered nested lists. Non-visual users may have
difficulties knowing where a list begins and ends and where each list item
starts. For example, if a list entry wraps to the next line on the screen, it
may appear to be two separate items in the list. This may pose a problem for
legacy screen readers.</p>
<h3>4.1 <a id="list-bullets" name="list-bullets">Use style sheets to change
list bullets</a></h3>
<p>To change the "bullet" style of unordered list items created with the <a
href="#edef-LI">LI</a> element, use style sheets. In CSS, it is possible to
specify a fallback bullet style (e.g., 'disc') if a bullet image cannot be
loaded.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<HEAD>
<TITLE>Using style sheets to change bullets</TITLE>
<STYLE type="text/css">
UL { list-style: url(star.gif) disc }
</STYLE>
</HEAD>
<BODY>
<UL>
<LI>Audrey
<LI>Laurie
<LI>Alice
</UL>
</pre>
<p class="off">End example.</p>
</div>
<p>To further ensure that users understand differences between list items
indicated visually, content developers should provide a text label before or
after the list item phrase:</p>
<div class="example">
<p><strong>Example.</strong></p>
<p>In this example, new information is communicated through text ("New"), font
style (bold), and color (yellow bullet, red text on yellow background).</p>
<pre>
<HEAD>
<TITLE>Bullet styles example</TITLE>
<STYLE type="text/css">
.newtxt { font-weight: bold;
color: red;
background-color: yellow }
.newbullet { list-style : url(yellow.gif) disc }
</STYLE>
</HEAD>
<BODY>
<UL>
<LI class="newbullet">Roth IRA <SPAN class="newtext">New</SPAN></LI>
<LI> 401(k)</LI>
</UL>
</BODY>
</pre>
<p class="off">End example.</p>
</div>
<h4>4.1.1 <a id="list-images" name="list-images">Images used as
bullets</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>Avoid using images as bullets in definition lists created with <a
href="#edef-DL">DL</a>, <a href="#edef-DT">DT</a>, and <a href="#edef-DD">
DD</a>. However, if this method is used, be sure to provide a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> for the images.</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<HEAD>
<TITLE>Deprecated example using image in DL lists</TITLE>
</HEAD>
<BODY>
<DL>
<DD><IMG src="star.gif" alt="* ">Audrey
<DD><IMG src="star.gif" alt="* ">Laurie
<DD><IMG src="star.gif" alt="* ">Alice
</DL>
</pre>
<p class="off">End example.</p>
</div>
<p>Content developers should avoid list styles where bullets provide additional
(visual) information. However, if this is done, be sure to provide a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> describing meaning of the bullet:</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<DL>
<DD><IMG src="red.gif" alt="New:">Roth IRA</DD>
<DD><IMG src="yellow.gif" alt="Old:">401(k)</DD>
</DL>
</pre>
<p class="off">End example.</p>
</div>
<h2>5 <a id="tables" name="tables">Tables</a></h2>
<p>This section discusses the accessibility of tables and elements that one can
put in a <a href="#edef-TABLE">TABLE</a> element. Two types of tables are
discussed: tables used to organize data, and tables used to create a visual
layout of the page.</p>
<h3>5.1 <a id="data-tables" name="data-tables">Tables of data</a></h3>
<p>Content developers may make HTML 4.01 data tables more accessible in a
number of ways:</p>
<ul>
<li>Providing summary information</li>
<li>Identifying row and column information</li>
</ul>
<h4>5.1.1 <a id="table-summary-info" name="table-summary-info">Providing
summary information</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-table-summaries"
class="noxref">5.5</a> Provide summaries for tables. [Priority 3]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-abbreviate-labels"
class="noxref">5.6</a> Provide abbreviations for header labels.
[Priority 3]</li>
</ul>
<ul>
<li>Provide a caption via the <a href="#edef-CAPTION">CAPTION</a> element. A
table caption describes the nature of the table in one to three sentences. Two
examples:
<ol>
<li>"Cups of coffee consumed by each senator."</li>
<li>"Who spends the most on pollution cleanup?"</li>
</ol>
A caption may not always be necessary.</li>
<li>If a CAPTION is not provided, use the "title" attribute on the TABLE
element to describe the nature of the table in a few words.</li>
<li>Provide a summary via the "<a href="#adef-summary">summary</a>" attribute.
Summaries are especially useful for non-visual readers. A summary of the
relationships among cells is especially important for tables with nested
headings, cells that span multiple columns or rows, or other relationships that
may not be obvious from analyzing the structure of the table but that may be
apparent in a visual rendering of the table. A summary may also describe how
the table fits into the context of the current document. If no caption is
provided, it is even more critical to provide a summary. Two examples:
<ol>
<li>"This table charts the number of cups of coffee consumed by each senator,
the type of coffee (decaf or regular), and whether taken with sugar."</li>
<li>"Total required by pollution control standards as of January 1, 1971.
Commercial category includes stores, insurance companies and banks. The table
is divided into two columns. The left-hand column is 'Total investment required
in billions of dollars'. The right--hand column is 'Spending' and is divided
into three sub-columns. The first sub-column is titled '1970 actual in millions
of dollars', the second is '1971 planned in millions of dollars', and the third
is 'Percent change, 1970 versus 1971.' The rows are industries." [NBA,
1996].</li>
</ol>
</li>
<li>Provide terse substitutes for header labels with the "<a
href="#adef-abbr">abbr</a>" attribute on TH. These will be particularly useful
for future speaking technologies that can read row and column labels for each
cell. Abbreviations cut down on repetition and reading time.</li>
</ul>
<!-- p>@@separate out the examples?</p -->
<h4>5.1.2 <a id="identifying-table-rows-columns"
name="identifying-table-rows-columns">Identifying rows and column
information</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-table-headers"
class="noxref">5.1</a> For data tables, identify row and column headers.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-table-structure"
class="noxref">5.2</a> For data tables that have two or more logical levels of
row or column headers, use markup to associate data cells and header cells.
[Priority 1]</li>
</ul>
<ul>
<li>Identify structural groups of rows (<a href="#edef-THEAD">THEAD</a> for
repeated table headers, <a href="#edef-TFOOT">TFOOT</a> for repeated table
footers, and <a href="#edef-TBODY">TBODY</a> for other groups of rows) and
groups of columns (<a href="#edef-COLGROUP">COLGROUP</a> and <a
href="#edef-COL">COL</a>).</li>
<li>Label table elements with the "<a href="#adef-scope">scope</a>", "<a
href="#adef-headers">headers</a>", and "<a href="#adef-axis">axis</a>"
attributes so that future browsers and assistive technologies will be able to
select data from a table by filtering on categories.</li>
<li>Do not use <a href="#edef-PRE">PRE</a> to create a tabular layout of text
-- use the TABLE element so that assistive technologies may recognize that it
is a table.</li>
<li>For information about table headers, refer to the table header algorithm
and discussion in the HTML 4.01 Recommendation (<cite><a href="#ref-HTML4"
title="Link to reference HTML4">[HTML4]</a></cite>, section 11.4.3).</li>
</ul>
<div class="example"><strong>Example.</strong>
<p>This example shows how to associate data cells (created with <a
href="#edef-TD">TD</a>) with their corresponding headers by means of the "<a
href="#adef-headers">headers</a>" attribute. The "headers" attribute specifies
a list of header cells (row and column labels) associated with the current data
cell. This requires each header cell to have an "id" attribute.</p>
<pre>
<TABLE border="1"
summary="This table charts the number of
cups of coffee consumed by each senator,
the type of coffee (decaf or regular),
and whether taken with sugar.">
<CAPTION>Cups of coffee consumed by each senator</CAPTION>
<TR>
<TH id="header1">Name</TH>
<TH id="header2">Cups</TH>
<TH id="header3" abbr="Type">Type of Coffee</TH>
<TH id="header4">Sugar?</TH>
<TR>
<TD headers="header1">T. Sexton</TD>
<TD headers="header2">10</TD>
<TD headers="header3">Espresso</TD>
<TD headers="header4">No</TD>
<TR>
<TD headers="header1">J. Dinnen</TD>
<TD headers="header2">5</TD>
<TD headers="header3">Decaf</TD>
<TD headers="header4">Yes</TD>
</TABLE>
</pre>
<p class="off">End example.</p>
</div>
<p>A speech synthesizer might render this tables as follows:</p>
<pre>
Caption: Cups of coffee consumed by each senator
Summary: This table charts the number of cups of coffee
consumed by each senator, the type of coffee
(decaf or regular), and whether taken with sugar.
Name: T. Sexton, Cups: 10, Type: Espresso, Sugar: No
Name: J. Dinnen, Cups: 5, Type: Decaf, Sugar: Yes
</pre>
<p>A visual user agent might render this table as follows:</p>
<p><img src="techimages/coffee-table.gif"
alt="Illustration of coffee table rendering"
longdesc="techimages/coffee-table-longdesc.html" /> <a
id="coffee-table-longdesc" name="coffee-table-longdesc" rel="Alternate"
href="techimages/coffee-table-longdesc.html">[Description of coffee
table]</a></p>
<p>The next example associates the same header (<a href="#edef-TH">TH</a>) and
data (<a href="#edef-TD">TD</a>) cells as before, but this time uses the "<a
href="#adef-scope">scope</a>" attribute rather than "<a
href="#adef-headers">headers</a>". "Scope" must have one of the following
values: "row", "col", "rowgroup", or "colgroup." Scope specifies the set of
data cells to be associated with the current header cell. This method is
particularly useful for simple tables. It should be noted that the spoken
rendering of this table would be identical to that of the previous example. A
choice between the "headers" and "scope" attributes is dependent on the
complexity of the table. It does not affect the output so long as the
relationships between header and data cells are made clear in the markup.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<TABLE border="1"
summary="This table charts ...">
<CAPTION>Cups of coffee consumed by each senator</CAPTION>
<TR>
<TH scope="col">Name</TH>
<TH scope="col">Cups</TH>
<TH scope="col" abbr="Type">Type of Coffee</TH>
<TH scope="col">Sugar?</TH>
<TR>
<TD>T. Sexton</TD> <TD>10</TD>
<TD>Espresso</TD> <TD>No</TD>
<TR>
<TD>J. Dinnen</TD> <TD>5</TD>
<TD>Decaf</TD> <TD>Yes</TD>
</TABLE>
</pre>
<p class="off">End example.</p>
</div>
<p>The following example shows how to create categories within a table using
the "<a href="#adef-axis">axis</a>" attribute.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<TABLE border="1">
<CAPTION>Travel Expense Report</CAPTION>
<TR>
<TH></TH>
<TH id="header2" axis="expenses">Meals
<TH id="header3" axis="expenses">Hotels
<TH id="header4" axis="expenses">Transport
<TD>subtotals</TD>
<TR>
<TH id="header6" axis="location">San Jose
<TH> <TH> <TH> <TD>
<TR>
<TD id="header7" axis="date">25-Aug-97
<TD headers="header6 header7 header2">37.74
<TD headers="header6 header7 header3">112.00
<TD headers="header6 header7 header4">45.00
<TD>
<TR>
<TD id="header8" axis="date">26-Aug-97
<TD headers="header6 header8 header2">27.28
<TD headers="header6 header8 header3">112.00
<TD headers="header6 header8 header4">45.00
<TD>
<TR>
<TD>subtotals
<TD>65.02
<TD>224.00
<TD>90.00
<TD>379.02
<TR>
<TH id="header10" axis="location">Seattle
<TH> <TH> <TH> <TD>
<TR>
<TD id="header11" axis="date">27-Aug-97
<TD headers="header10 header11 header2">96.25
<TD headers="header10 header11 header3">109.00
<TD headers="header10 header11 header4">36.00
<TD>
<TR>
<TD id="header12" axis="date">28-Aug-97
<TD headers="header10 header12 header2">35.00
<TD headers="header10 header12 header3">109.00
<TD headers="header10 header12 header4">36.00
<TD>
<TR>
<TD>subtotals
<TD>131.25
<TD>218.00
<TD>72.00
<TD>421.25
<TR>
<TH>Totals
<TD>196.27
<TD>442.00
<TD>162.00
<TD>800.27
</TABLE>
</pre>
<p class="off">End example.</p>
</div>
<p>This table lists travel expenses at two locations: San Jose and Seattle, by
date, and category (meals, hotels, and transport). The following image shows
how a visual user agent might render it. <a id="travel-report-longdesc"
name="travel-report-longdesc" rel="Alternate"
href="techimages/travel-report-longdesc.html">[Description of travel
table]</a></p>
<p><img src="techimages/table1.gif"
alt="Travel Expense Report table as rendered by a visual user agent."
longdesc="techimages/travel-report-longdesc.html" /></p>
<h3>5.2 <a id="tables-layout" name="tables-layout">Tables for layout</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-table-for-layout"
class="noxref">5.3</a> Do not use tables for layout unless the table makes
sense when linearized. Otherwise, if the table does not make sense, provide an
alternative equivalent (which may be a linearized version).
[Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-table-layout"
class="noxref">5.4</a> If a table is used for layout, do not use any structural
markup for the purpose of visual formatting. [Priority 2]</li>
</ul>
<p>Authors should use style sheets for <a
href="http://www.w3.org/TR/WCAG10-CSS-TECHS/#style-alignment">layout and
positioning</a>. However, when it is necessary to use a table for layout, the
table must linearize in a readable order. When a table is linearized, the
contents of the cells become a series of paragraphs (e.g., down the page) one
after another. Cells should make sense when read in row order and should
include structural elements (that create paragraphs, headings, lists, etc.) so
the page makes sense after linearization.</p>
<p>Also, when using tables to create a layout, do not use structural markup to
create visual formatting. For example, the TH (table header) element, is
usually displayed visually as centered, and bold. If a cell is not actually a
header for a row or column of data, use style sheets or formatting attributes
of the element.</p>
<h3>5.3 <a id="wrapped-text" name="wrapped-text">Linearizing tables</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-linear-tables"
class="noxref">10.3</a> Until user agents (including assistive technologies)
render side-by-side text correctly, provide a linear text alternative (on the
current page or some other) for <em>all</em> tables that lay out text in
parallel, word-wrapped columns. [Priority 3]</li>
</ul>
<p>Tables used to lay out pages where cell text wraps pose problems for older
screen readers that do not interpret the source HTML or browsers that do not
allow navigation of individual table cells. These screen readers will read
across the page, reading sentences on the same row from different columns as
one sentence.</p>
<p>For example, if a table is rendered like this on the screen:</p>
<pre>
There is a 30% chance of Classes at the University of Wisconsin
rain showers this morning, but they will resume on September 3rd.
should stop before the weekend.
</pre>
<p>This might be read by a screen reader as:</p>
<pre>
There is a 30% chance of Classes at the University of Wisconsin
rain showers this morning, but they will resume on September 3rd.
should stop before the weekend.
</pre>
<!-- p>Screen readers that read the source HTML will recognize the
structure of each cell, but for older screen readers, content
developers may minimize the risk of word wrapping by limiting the
amount of text in each cell. Also, the longest chunks of text should
all be in the last column (rightmost for left-to-right tables). This
way, if they wrap, they will still be read coherently. Content
developers should test tables for wrapping with a browser window
dimension of "640x480".</p -->
<!-- P>Since table markup is structural, and we suggest separating structure
from presentation, we recommend using style sheets to create layout,
alignment, and presentation effects. Thus, the two columns in the
above example could have been created using style sheets. Please refer
to the section on style sheets for more information.</p -->
<p>It is usually very simple to linearize a table used to layout a page -
simply strip the table markup from the table. There are several tools that do
this, and it is becoming more common for screen readers and some browsers to
linearize tables.</p>
<p>However, linearizing <a href="#data-tables">data tables</a> requires a
different strategy. Since data cells rely on the information provided by
surrounding and header cells, the relationship information that is available
visually needs to be translated into the linear table.</p>
<p>For example, specify the column layout order. The natural language writing
direction may affect column layout and thus the order of a linearized table.
The "<a href="#adef-dir">dir</a>" attribute specifies column layout order
(e.g., dir="rtl" specifies right-to-left layout).</p>
<!-- p>@@also the case for layout tables?</p --><!-- p>@@example</p -->
<!-- p> @@again, there are tools to help produce linearized versions of data tables.
We will provide a link </p -->
<p>This markup will also help browsers linearize tables (also called table
"serialization"). A row-based linear version may be created by reading the row
header, then preceding each cell with the cell's column header. Or, the
linearization might be column-based. Future browsers and assistive technologies
will be able to automatically translate tables into linear sequences or
navigate a table cell by cell if data is labeled appropriately. The WAI
Evaluation and Repair working group is tracking the progress of tools as well
as developing their own that will allow users to linearize or navigate tables
cell by cell. Refer to <cite><a href="#ref-WAI-ER"
title="Link to reference WAI-ER">[WAI-ER]</a></cite>.</p>
<p><span class="quicktest">Quicktest!</span> To get a better understanding of
how a screen reader would read a table, run a piece of paper down the page and
read your table line by line.</p>
<h3>5.4 <a id="bc-tables" name="bc-tables">Backward compatibility issues for
tables</a></h3>
<!-- p>@@checkpoint that this can fit under?</p -->
<p>In HTML 3.2 browsers, the rows of a <a href="#edef-TFOOT">TFOOT</a> element
will appear before the table body.
<!-- Used to say "before the BODY of the document" which
I don't think is true. -IJ --></p>
<h2>6 <a id="links" name="links">Links</a></h2>
<h3>6.1 <a id="link-text" name="link-text">Link text</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-meaningful-links"
class="noxref">13.1</a> Clearly identify the target of each link.
[Priority 2]</li>
</ul>
<p>Good link text should not be overly general; don't use "click here." Not
only is this phrase device-dependent (it implies a pointing device) it says
nothing about what is to be found if the link if followed. Instead of "click
here", link text should indicate the nature of the link target, as in "more
information about sea lions" or "text-only version of this page". Note that for
the latter case (and other format- or language-specific documents), content
developers are encouraged to use <a
href="http://www.w3.org/TR/WCAG10-CORE-TECHS/#content-negotiation">content
negotiation</a> instead, so that users who prefer text versions will have them
served automatically.</p>
<p>In addition to clear link text, content developers may specify a value of
the "title" attribute that clearly and accurately describes the target of the
link.</p>
<p><a id="link-consistent" name="link-consistent">If more than one link on a
page shares the same link text, all those links should point to the same
resource.</a> Such consistency will help page design as well as
accessibility.</p>
<p>If two or more links refer to different targets but share the same link
text, distinguish the links by specifying a different value for the "<a
href="#adef-title">title</a>" attribute of each <a href="#edef-A">A</a>
element.</p>
<p>"Auditory users" -- people who are blind, have difficulty seeing, or who are
using devices with small or no displays -- are unable to scan the page quickly
with their eyes. To get an overview of a page or to quickly find a link, these
users will often tab from one link to the next or review a list of available
links on a page.</p>
<p>Thus, for a series of related links, include introductory information in the
first link, then distinguishing information in the links that follow. This will
provide context information for users reading them in sequence.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<A href="my-doc.html">My document is available in HTML</A>,
<A href="my-doc.pdf" title="My document in PDF">PDF</A>,
<A href="my-doc.txt" title="My document in text">plain text</A>
</pre>
<p class="off">End example.</p>
</div>
<h4>6.1.1 <a id="link-text-images" name="link-text-images">Text for images used
as links</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>When an image is used as the content of a link, specify a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> for the image.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<A href="routes.html">
<IMG src="topo.html"
alt="Current routes at Boulders Climbing Gym">
</A>
</pre>
<p class="off">End example.</p>
</div>
<p>Or, if you provide link text, use a space as the "alt" attribute value of
the IMG element. Note that this text will appear on the page next to the
image.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<A href="routes.html">
<IMG src="topo.html" alt=" ">
Current routes at Boulders Climbing Gym
</A>
</pre>
<p class="off">End example.</p>
</div>
<h3>6.2 <a id="group-bypass" name="group-bypass">Grouping and bypassing
links</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-group-links"
class="noxref">13.6</a> Group related links, identify the group (for user
agents), and, until user agents do so, provide a way to bypass the group.
[Priority 3]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-divide-links"
class="noxref">10.5</a> Until user agents (including assistive technologies)
render adjacent links distinctly, include non-link, printable characters
(surrounded by spaces) between adjacent links. [Priority 3]</li>
</ul>
<p>When links are grouped into logical sets (for example, in a navigation bar
that appears on every page in a site) they should be marked up as a unit.
Navigation bars are usually the first thing someone encounters on a page. For
users with speech synthesizers, this means having to hear a number of links on
every page before reaching the interesting content of a page. There are several
ways to allow users to bypass groups of links (as users with vision do when
they see the same set on each page):</p>
<ul>
<li>Include a link that allows users to skip over the set of navigation links.
<!-- LI>Use the HTML 4.01 "<a href="#adef-tabindex">tabindex</a>"
attribute to allow users to jump to an anchor after the set of
navigation links. This attribute is not yet widely supported. </li --></li>
<li>Provide a style sheet that allows users to hide the set of navigation
links.</li>
<li>Use the HTML 4.01 MAP element to group links, then identify the group with
the "<a href="#adef-title">title</a>" attribute.</li>
</ul>
<p>In the future, user agents may allow users to skip over elements such as
navigation bars.</p>
<div class="example">
<p><strong>Example.</strong></p>
<p>In this example, the <a href="#edef-MAP">MAP</a> element groups a set of
links, the "title" attribute identifies it as a navigation bar ,
<!-- "<a href="#adef-tabindex">tabindex</a>" is set
on an anchor following the group, --> and a link at the beginning of the group
links to the anchor after the group. Also, note that the links are separated by
non-link, printable characters (surrounded by spaces).</p>
<pre>
<BODY>
<MAP title="Navigation Bar">
<P>
[<A href="#how">Bypass navigation bar</A>]
[<A href="home.html">Home</A>]
[<A href="search.html">Search</A>]
[<A href="new.html">New and highlighted</A>]
[<A href="sitemap.html">Site map</A>]
</P>
</MAP>
<H1><A name="how">How to use our site</A></H1>
<!-- content of page -->
</BODY>
</pre>
<p class="off">End example.</p>
</div>
<h3>6.3 <a id="link-accesskey" name="link-accesskey">Keyboard access</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-tab-order" class="noxref">
9.4</a> Create a logical tab order through links, form controls, and objects.
[Priority 3]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-keyboard-shortcuts"
class="noxref">9.5</a> Provide keyboard shortcuts to important links (including
those in client-side image maps), form controls, and groups of form controls.
[Priority 3]</li>
</ul>
<p>Keyboard access to active elements of a page is important for many users who
cannot use a pointing device. User agents may include features that allow users
to bind keyboard strokes to certain actions. HTML 4.01 allows content
developers to specify keyboard shortcuts in documents via the "<a
href="#adef-accesskey">accesskey</a>" attribute.</p>
<div class="example">
<p><strong>Example.</strong></p>
<p>In this example, if the user activates the "C" key, the link will be
followed.</p>
<pre>
<A accesskey="C" href="doc.html" hreflang="en"
title="XYZ company home page">
XYZ company home page</A>
</pre>
<p class="off">End example.</p>
</div>
<p>Note: Until user agents provide an overview of which key bindings are
available, provide information on the key bindings.</p>
<h3>6.4 <a id="anchors-targets" name="anchors-targets">Anchors and
targets</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-pop-ups"
class="noxref">10.1</a> Until user agents allow users to turn off spawned
windows, do not cause pop-ups or other windows to appear and do not change the
current window without informing the user. [Priority 2]</li>
</ul>
<!-- p>@@include info about using target attribute on A to generate new
windows. test that an unknown target causes a new window to open.</p -->
<h2>7 <a id="images" name="images">Images and image maps</a></h2>
<p>The following sections discuss accessibility of images (including simple
animations such as GIF animations) and image maps.</p>
<p>For information about math represented as images, refer to the section on <a
href="#text-markup">using text markup and style sheets rather than
images</a>.</p>
<h3>7.1 <a id="image-text-equivalent" name="image-text-equivalent">Short text
equivalents for images ("alt-text")</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video. [Priority 1]
.</li>
</ul>
<p>When using <a href="#edef-IMG">IMG</a>, specify a short <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> with the "<a href="#adef-alt">alt</a>" attribute. <strong>
Note.</strong> The value of this attribute is referred to as "alt-text".</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<IMG src="magnifyingglass.gif" alt="Search">
</pre>
<p class="off">End example.</p>
</div>
<p><a id="object-alt" name="object-alt">When using</a> <a href="#edef-OBJECT">
OBJECT</a>, specify a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> in the body of the OBJECT element:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT data="magnifyingglass.gif" type="image/gif">
Search
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<h3>7.2 <a id="long-descriptions" name="long-descriptions">Long descriptions of
images</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>When a short text equivalent does not suffice to adequately convey the
function or role of an image, provide additional information in a file
designated by the "<a href="#adef-longdesc">longdesc</a>" attribute:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<IMG src="97sales.gif" alt="Sales for 1997"
longdesc="sales97.html">
</pre>
<p>In sales97.html:</p>
<blockquote>
<p>A chart showing how sales in 1997 progressed. The chart<br />
is a bar-chart showing percentage increases in sales<br />
by month. Sales in January were up 10% from December 1996,<br />
sales in February dropped 3%, ..</p>
</blockquote>
<p class="off">End example.</p>
</div>
<p><a id="img-dlink" name="img-dlink">For user agents that don't support
"longdesc",</a> provide a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-d-link">description link</a> as
well next to the graphic:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<IMG src="97sales.gif" alt="Sales for 1997" longdesc="sales.html">
<A href="sales.html" title="Description of 1997 sales figures">[D]</A>
</pre>
<p class="off">End example.</p>
</div>
<p>When using OBJECT, specify longer text equivalent within the element's
content:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT data="97sales.gif" type="image/gif">
Sales in 1997 were down subsequent to our
<A href="anticipated.html">anticipated
purchase</A> ...
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<p>Note that OBJECT content, unlike "alt" text, can include markup. Thus,
content developers can provide a link to additional information from within the
OBJECT element:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT data="97sales.gif" type="image/gif">
Chart of our Sales in 1997.
A <A href="desc.html">textual description</A> is available.
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<h4>7.2.1 <a id="img-dlink-invis" name="img-dlink-invis">Invisible
d-links</a></h4>
<p><strong>Note. Invisible d-links are deprecated in favor of the "longdesc"
attribute</strong>.</p>
<p>An invisible <a href="http://www.w3.org/TR/WCAG10-TECHS/#def-d-link">
d-link</a> is a small (1-pixel) or transparent image whose "<a
href="#adef-alt">alt</a>" attribute value is "D-link" or "D" and is part of the
content of an <a href="#edef-A">A</a> element. Like other d-links, it refers to
a text equivalent of the associated image. Like other links, users can tab to
it. Invisible d-links thus provide a (temporary) solution for designers who
wish to avoid visible d-links for stylistic reasons.</p>
<h3>7.3 <a id="ascii-art" name="ascii-art">Ascii art</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-skip-over-ascii"
class="noxref">13.10</a> Provide a means to skip over multi-line ASCII art.
[Priority 3]</li>
</ul>
<p><a id="avoid-ascii-art" name="avoid-ascii-art">Avoid ASCII art</a>
(character illustrations) and use real images instead since it is easier to
supply a <a href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> for images. However, if <acronym
title="American Standard Code for Information Interchange">ASCII</acronym> art
must be used provide a link to jump over the ASCII art, as follows.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<P>
<a href="#post-art">skip over ASCII art</a>
<!-- ASCII art goes here -->
<a name="post-art">caption for ASCII art</a>
</pre>
<p class="off">End example.</p>
</div>
<p>ASCII art may also be marked up as follows [<a id="ascii-chart"
name="ascii-chart" href="#after-ascii-chart">skip over ASCII figure</a> or
consult a <a rel="Alternate" href="techimages/ascii-chart-longdesc.html">
description of chart</a>]:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre
title="Figure showing the percentage of photosensitive patients in whom a photoconvulsive response was elicited by a 2 second train of flashes with eyes open and closed.">
% __ __ __ __ __ __ __ __ __ __ __ __ __ __
100 | * |
90 | * * |
80 | * * |
70 | @ * |
60 | @ * |
50 | * @ * |
40 | @ * |
30 | * @ @ @ * |
20 | |
10 | @ @ @ @ @ |
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Flash frequency (Hz)
</pre>
<p class="off">End example.</p>
</div>
<p><a id="after-ascii-chart" name="after-ascii-chart">Another option</a> for
smaller ascii art is to use an <a href="#edef-ABBR">ABBR</a> element with "<a
href="#adef-title">title</a>".</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<P><ABBR title="smiley in ASCII art">:-)</ABBR>
</pre>
<p class="off">End example.</p>
</div>
<p>If the ASCII art is complex, ensure that the text equivalent adequately
describes it.</p>
<p>Another way to replace <acronym
title="American Standard Code for Information Interchange">ASCII</acronym> art
is to use human language substitutes. For example, <wink> might
substitute for a winking smiley: <abbr title="winking smiley">;-)</abbr>. Or,
the word "therefore" can replace arrows consisting of dashes and greater than
signs (e.g., -->), and the word "great" for the uncommon abbreviation
"gr8".</p>
<h3>7.4 <a id="image-maps" name="image-maps">Image maps</a></h3>
<p>An image map is an image that has "active regions". When the user selects
one of the regions, some action takes place -- a link may be followed,
information may be sent to a server, etc. To make an image map accessible,
content developers must ensure that each action associated with a visual region
may be activated without a pointing device.</p>
<!-- Fix the following and the related example
as per:
http://lists.w3.org/Archives/Public/w3c-wai-gl/1999JanMar/0439.html
-->
<p>Image maps are created with the <a href="#edef-MAP">MAP</a> element. HTML
allows two types of image maps: client-side (the user's browser processes a
URI) and server-side (the server processes click coordinates). For all image
maps, content developers must supply a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a>.</p>
<p>Content developers should create client-side image maps (with "<a
href="#adef-usemap">usemap</a>") rather than server-side image maps (with "<a
href="#adef-ismap">ismap</a>") because server-side image maps require a
specific input device. If server-side image maps must be used (e.g., because
the geometry of a region cannot be represented with values of the <a
href="#adef-shape">shape</a> attribute), authors must provide the same
functionality or information in an alternative accessible format. One way to
achieve this is to provide a textual link for each active region so that each
link is navigable with the <a href="#link-accesskey">keyboard</a>. If you must
use a server-side image map, please consult the section on <a
href="#server-side">server-side image maps</a></p>
<!-- Include example for server-side since more important. done - but comes
later, in the server-side section. -->
<h4>7.4.1 <a id="client-side-text-equivs" name="client-side-text-equivs">Text
equivalents for client-side image maps</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>Provide <a href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">
text equivalents</a> for image maps since they convey visual information. As
with other links, the link text should make sense when read out of context.
Refer to <a href="#link-text">the section on Link Text</a> for information on
writing good link text. Users may also want keyboard shortcuts to access
frequently followed links. Refer to <a href="#link-accesskey">the section on
Keyboard access to links</a>.</p>
<p>If <a href="#edef-AREA">AREA</a> is used to create the map, use the "<a
href="#adef-alt">alt</a>" attribute:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<IMG src="welcome.gif" alt="Image map of areas in the library"
usemap="#map1">
<MAP name="map1">
<AREA shape="rect" coords="0,0,30,30"
href="reference.html" alt="Reference">
<AREA shape="rect" coords="34,34,100,100"
href="media.html" alt="Audio visual lab">
</MAP>
</pre>
<p class="off">End example.</p>
</div>
<p>The following example illustrates the same idea, but uses <a
href="#edef-OBJECT">OBJECT</a> instead of IMG to insert the image to provide
more information about the image:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT data="welcome.gif" type="image/gif" usemap="#map1">
There are several areas in the library including
the <A href="reference.html">Reference</A> section and the
<A href="media.html">Audio Visual Lab</A>.
</OBJECT>
<MAP name="map1">
<AREA shape="rect" coords="0,0,30,30"
href="reference.html" alt="Reference">
<AREA shape="rect" coords="34,34,100,100"
href="media.html" alt="Audio visual lab">
</MAP>
</pre>
<p class="off">End example.</p>
</div>
<h4>7.4.2 <a id="client-side-redundant-text" name="client-side-redundant-text">
Redundant text links for client-side image maps</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-redundant-client-links"
class="noxref">1.5</a> Until user agents render text equivalents for
client-side image map links, provide redundant text links for each active
region of a client-side image map. [Priority 3]</li>
</ul>
<p>In addition to providing a text equivalent, provide redundant textual links.
If the <a href="#edef-A">A</a> element is used instead of AREA, the content
developer may describe the active regions and provide redundant links at the
same time:</p>
<div class="example">
<p><strong><a id="object-example" name="object-example">
Example.</a></strong></p>
<pre>
<OBJECT data="navbar1.gif" type="image/gif" usemap="#map1">
<MAP name="map1">
<P>Navigate the site.
[<A href="guide.html" shape="rect"
coords="0,0,118,28">Access Guide</A>]
[<A href="shortcut.html" shape="rect"
coords="118,0,184,28">Go</A>]
[<A href="search.html" shape="circle"
coords="184.200,60">Search</A>]
[<A href="top10.html" shape="poly"
coords="276,0,276,28,100,200,50,50,276,0">
Top Ten</A>]
</MAP>
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<p>Note that in the previous example, the MAP element is the content of the
OBJECT element so that the alternative links will only be displayed if the
image map (navbar1.gif) is not.</p>
<p>Note also that links have been separated by brackets ([]). This is to
prevent older screen readers from reading several adjacent links as a single
link as well as to help sighted users distinguish between links visually.</p>
<p>Content developers should make sure they include printable characters (such
as brackets or a vertical bar (|)) surrounded by spaces between adjacent text
links. The problem does not occur if images have been used as links; The
alt-text will not be read as a single link because of the place-holding images
that graphical browsers use when images are not loaded. Refer to the section <a
href="#group-bypass">Grouping and bypassing links</a> for more information.</p>
<h4>7.4.3 <a id="client-vs-server-side" name="client-vs-server-side">
Client-side versus server-side image maps</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-client-side-maps"
class="noxref">9.1</a> Provide client-side image maps instead of server-side
image maps except where the regions cannot be defined with an available
geometric shape. [Priority 1]</li>
</ul>
<!-- p>@@discuss reasoning why we suggest client- vs. server-side image maps. Discuss tools
to use to convert server-side to client-side. Find a good example of a server-side image
map.</p -->
<h4>7.4.4 <a id="server-side" name="server-side">Server-side image
maps</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-redundant-server-links"
class="noxref">1.2</a> Provide redundant text links for each active region of a
server-side image map. [Priority 1]</li>
</ul>
<p>When a server-side image map must be used, content developers should provide
an alternative list of image map choices. There are three techniques:</p>
<ul>
<li>Include the alternative links within the body of an <a href="#edef-OBJECT">
OBJECT</a> element (refer to the previous <a href="#object-example">example
illustrating links in the OBJECT element</a>).</li>
<li>If <a href="#edef-IMG">IMG</a> is used to insert the image, provide an
alternative list of links after it and indicate the existence and location of
the alternative list (e.g., via that "<a href="#adef-alt">alt</a>" attribute).
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<A href="http://www.example.com/cgi-bin/imagemap/my-map">
<IMG src="welcome.gif" alt="Welcome! (Text links follow)" ismap>
</A>
<P>[<A href="reference.html">Reference</A>]
[<A href="media.html">Audio Visual Lab</A>]
</pre>
<p class="off">End example.</p>
</div>
</li>
<li>If other approaches don't make the image map accessible, create an <a
href="http://www.w3.org/TR/WCAG10-TECHS/#alt-page-note">alternative page</a>
that is accessible.</li>
</ul>
<p>Server-side and client-side image maps may be used as submit buttons in
Forms. For more information, refer to the section <a
href="#forms-graphical-buttons">Graphical buttons</a>.</p>
<h3>7.5 <a id="color-images" name="color-images">Color in images</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-color-contrast"
class="noxref">2.2</a> Ensure that foreground and background color combinations
provide sufficient contrast when viewed by someone having color deficits or
when viewed on a black and white screen. [Priority 2 for images,
Priority 3 for text].</li>
</ul>
<!-- p>@@discuss contrast issues with regard to images</p -->
<h3>7.6 <a id="animated-images" name="animated-images">Animated images</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-movement"
class="noxref">7.3</a> Until user agents allow users to freeze moving content,
avoid movement in pages. [Priority 2]</li>
</ul>
<!-- p>@@discuss avoiding movement caused by animated gifs.</p -->
<h2>8 <a id="objects" name="objects">Applets and other programmatic
objects</a></h2>
<p>While applets may be included in a document with either the <a
href="#edef-APPLET">APPLET</a> or <a href="#edef-OBJECT">OBJECT</a> element, <a
href="#edef-OBJECT">OBJECT</a> is the preferred method.</p>
<h3>8.1 <a id="applet-text-equivalent" name="applet-text-equivalent">Text and
non-text equivalents for applets and programmatic objects</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-dynamic-source"
class="noxref">6.2</a> Ensure that equivalents for dynamic content are updated
when the dynamic content changes. [Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-scripts" class="noxref">
6.3</a> Ensure that pages are usable when scripts, applets, or other
programmatic objects are turned off or not supported. If this is not possible,
provide equivalent information on an alternative accessible page.
[Priority 1]</li>
</ul>
<p>If <a href="#edef-OBJECT">OBJECT</a> is used, provide a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> in the content of the element:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT classid="java:Press.class" width="500" height="500">
As temperature increases, the molecules in the balloon...
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<p>A more complex example takes advantage of the fact the OBJECT elements may
be embedded to provide for alternative representations of information:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<OBJECT classid="java:Press.class" width="500" height="500">
<OBJECT data="Pressure.mpeg" type="video/mpeg">
<OBJECT data="Pressure.gif" type="image/gif">
As temperature increases, the molecules in the balloon...
</OBJECT>
</OBJECT>
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<p>If <a href="#edef-APPLET">APPLET</a> is used, provide a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> with the "<a href="#adef-alt">alt</a>" attribute <em>and</em> in
the content in the APPLET element. This enables the content to transform
gracefully for those user agents that only support one of the two mechanisms
("alt" or content).</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<APPLET code="Press.class" width="500" height="500"
alt="Java applet: how temperature affects pressure">
As temperature increases, the molecules in the balloon...
</APPLET>
</pre>
<p class="off">End example.</p>
</div>
<h3>8.2 <a id="accessible-applets" name="accessible-applets">Directly
accessible applets</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-directly-accessible"
class="noxref">8.1</a> Make programmatic elements such as scripts and applets
directly accessible or compatible with assistive technologies [Priority 1
if functionality is important and not presented elsewhere, otherwise
Priority 2.]</li>
</ul>
<p>If an applet (created with either <a href="#edef-OBJECT">OBJECT</a> or <a
href="#edef-APPLET">APPLET</a>) requires user interaction (e.g., the ability to
manipulate a physics experiment) that cannot be duplicated in an alternative
format, make the applet directly accessible.</p>
<p>If an applet creates motion, developers should provide a mechanism for
freezing this motion (for an example, refer to <cite><a href="#ref-TRACE"
title="Link to reference TRACE">[TRACE]</a></cite>). Also, please refer to the
next section for information about making audio and video presentations
accessible.</p>
<p>For more information about developing accessible applets, please refer to
<cite><a href="#ref-JAVAACCESS" title="Link to reference JAVAACCESS">
[JAVAACCESS]</a></cite> and <cite><a href="#ref-IBMJAVA"
title="Link to reference IBMJAVA">[IBMJAVA]</a></cite>. These companies have
been developing an Accessibility API as well as making the Java Swing classes
accessible.</p>
<p>Related checkpoints:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-relative-units"
class="noxref">3.4</a> Use relative rather than absolute units in markup
language attribute values and style sheet property values. [Priority 2]
,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-keyboard-operable-scripts"
class="noxref">6.4</a> For scripts and applets, ensure that event handlers are
input device-independent. [Priority 2] ,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-fallback-page"
class="noxref">6.5</a> Ensure that dynamic content is accessible or provide an
alternative presentation or page. [Priority 2] ,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-flicker"
class="noxref">7.1</a> Until user agents allow users to control flickering,
avoid causing the screen to flicker. [Priority 1] ,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-blinking"
class="noxref">7.2</a> Until user agents allow users to control blinking, avoid
causing content to blink (i.e., change presentation at a regular rate, such as
turning on and off). [Priority 2] ,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-movement"
class="noxref">7.3</a> Until user agents allow users to freeze moving content,
avoid movement in pages. [Priority 2] ,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-no-periodic-refresh"
class="noxref">7.4</a> Until user agents provide the ability to stop the
refresh, do not create periodically auto-refreshing pages. [Priority 2]
,</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-keyboard-operable"
class="noxref">9.2</a> Ensure that any element that has its own interface can
be operated in a device-independent manner. [Priority 2] ,</li>
<li>and <a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-pop-ups"
class="noxref">10.1</a> Until user agents allow users to turn off spawned
windows, do not cause pop-ups or other windows to appear and do not change the
current window without informing the user. [Priority 2] .</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-synchronize-equivalents"
class="noxref">1.4</a> For any time-based multimedia presentation (e.g., a
movie or animation), synchronize equivalent alternatives (e.g., captions or
auditory descriptions of the visual track) with the presentation.
[Priority 1]</li>
</ul>
<h2>9 <a id="audio-and-video" name="audio-and-video">Audio and video</a></h2>
<!-- Add information about CSS2 ACSS and SMIL control of cueing,
parallel sounds -->
<h3>9.1 <a id="audio-information" name="audio-information">Audio
information</a></h3>
<h3>9.2 <a id="text-equivs-multimedia" name="text-equivs-multimedia">Text
equivalents for multimedia</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>When necessary, a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> should be provided for visual information to enable
understanding of the page. For example, consider a repeating animation that
shows cloud cover and precipitation as part of a weather status report. Since
the animation is supplementing the rest of the weather report (that is
presented in natural language - text), a less verbose description of the
animation is necessary. However, if the animation appears in a pedagogical
setting where students are learning about cloud formations in relation to land
mass, then the animation ought to be described for those who can not view the
animation but who also want to learn the lesson.</p>
<!-- why is this in this section?? <p>See also the section on
<a href="http://www.w3.org/TR/WCAG10-CSS-TECHS/#style-text">text style</a> for
controlling blinking.</p> -->
<h3>9.3 <a id="embed-multimedia" name="embed-multimedia">Embedding multimedia
objects</a></h3>
<p>Other objects, such as those requiring a plug-in, should also use the <a
href="#edef-OBJECT">OBJECT</a> element. However, for backward compatibility
with Netscape browsers, use the proprietary EMBED element within the OBJECT
element as follows:</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<OBJECT classid="clsid:A12BCD3F-GH4I-56JK-xyz"
codebase="http://example.com/content.cab" width=100 height=80>
<PARAM name="Movie" value="moviename.swf">
<EMBED src="moviename.swf" width=100 height=80
pluginspage="http://example.com/shockwave/download/">
</EMBED>
<NOEMBED>
<IMG alt="Still from Movie"
src="moviename.gif" width=100 height=80>
</NOEMBED>
</OBJECT>
</pre>
<p class="off">End example.</p>
</div>
<p>For more information refer to <cite><a href="#ref-MACROMEDIA"
title="Link to reference MACROMEDIA">[MACROMEDIA]</a></cite>.</p>
<h2>10 <a id="frames" name="frames">Frames</a></h2>
<p>For visually enabled users, frames may organize a page into different zones.
For non-visual users, relationships between the content in frames (e.g., one
frame has a table of contents, another the contents themselves) must be
conveyed through other means.</p>
<p>Frames as implemented today (with the <a href="#edef-FRAMESET">FRAMESET</a>,
<a href="#edef-FRAME">FRAME</a>, and <a href="#edef-IFRAME">IFRAME</a>
elements) are problematic for several reasons:</p>
<ul>
<li>Without scripting, they tend to break the "previous page" functionality
offered by browsers.</li>
<li>It is impossible to refer to the "current state" of a frameset with a URI;
once a frameset changes contents, the original URI no longer applies.</li>
<li>Opening a frame in a new browser window can disorient or simply annoy
users.</li>
</ul>
<p>In the following sections, we discuss how to make frames more accessible. We
also provide an <a href="#alt-frames">alternative to frames</a> that uses HTML
4.01 and CSS and addresses many of the limitations of today's frame
implementations.</p>
<h3>10.1 <a id="frame-names" name="frame-names">Providing a frame
title</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-frame-titles"
class="noxref">12.1</a> Title each frame to facilitate frame identification and
navigation. [Priority 1]</li>
</ul>
<div class="example">
<p><strong>Example.</strong></p>
<p>Use the "title" attribute to name frames.</p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>A simple frameset document</TITLE>
</HEAD>
<FRAMESET cols="10%, 90%"
title="Our library of electronic documents">
<FRAME src="nav.html" title="Navigation bar">
<FRAME src="doc.html" title="Documents">
<NOFRAMES>
<A href="lib.html" title="Library link">
Select to go to the electronic library</A>
</NOFRAMES>
</FRAMESET>
</pre>
<p class="off">End example.</p>
</div>
<h3>10.2 <a id="frame-text-equivalent" name="frame-text-equivalent">Describing
frame relationships</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-frame-longdesc"
class="noxref">12.2</a> Describe the purpose of frames and how frames relate to
each other if it is not obvious by frame titles alone. [Priority 2]</li>
</ul>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>Today's news</TITLE>
</HEAD>
<FRAMESET cols="10%,*,10%">
<FRAMESET rows="20%,*">
<FRAME src="promo.html" name="promo" title="promotions">
<FRAME src="sitenavbar.html" name="navbar"
title="Sitewide navigation bar" longdesc="frameset-desc.html#navbar">
</FRAMESET>
<FRAME src="story.html" name="story" title="Selected story - main content"
longdesc="frameset-desc.html#story">
<FRAMESET rows="*,20%">
<FRAME src="headlines.html" name="index" title="Index of other
national headlines" longdesc="frameset-desc.html#headlines">
<FRAME src="ad.html" name="adspace" title="Advertising">
</FRAMESET>
<NOFRAMES>
<p><a href="noframes.html">No frames version</a></p>
<p><a href="frameset-desc.html">Descriptions of frames.</a></p>
</NOFRAMES>
</FRAMESET>
</HTML>
</pre>
<p>frameset-desc.html might say something like:</p>
<pre>
#Navbar - this frame provides links to the major
sections of the site: World News, National News,
Local News, Technological News,
and Entertainment News.
#Story - this frame displays the currently selected story.
#Index - this frame provides links to the day's
headline stories within this section.
</pre>
<p class="off">End example.</p>
</div>
<p>Note that if the a frame's contents change, the text equivalent will no
longer apply. Also, links to descriptions of a frame should be provided along
with other alternative content in the <a href="#edef-NOFRAMES">NOFRAMES</a>
element of a <a href="#edef-FRAMESET">FRAMESET</a>.
<!-- Long descriptions of frames should only
be used for frames with static contents. not necessarily so - depending on
the frame and how longdesc is written. WC --></p>
<!-- I commented out this example in favor of the current one. perhaps add it
in as a way to show how the longdesc won't always be applicable?
<div class="example">
<p><strong>Example.</strong></p>
<p>In this example, the file "chart.html" inserts a complex chart.
The "longdesc" attribute designates the file "chart-desc.html",
which contains a long description of the chart.</p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>A simple frameset document</TITLE>
</HEAD>
<FRAMESET cols="20%, 80%">
<FRAME src="table_of_contents.html">
<FRAME src="chart.html" longdesc="chart-desc.html">
</FRAMESET>
</pre>
<p>Note that if the second frame's contents change (from"chart.html"), the long description will no longer apply. Long
descriptions of frames should only be used for frames with static
contents.</p>
<p class="off">End example.</p>
</div>
-->
<h3>10.3 <a id="noframes" name="noframes">Writing for browsers that do not
support FRAME</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-fallback-page"
class="noxref">6.5</a> Ensure that dynamic content is accessible or provide an
alternative presentation or page. [Priority 2]</li>
</ul>
<div class="example">
<p><strong>Example.</strong></p>
<p>In this example, if the user reads "top.html":</p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>This is top.html</TITLE>
</HEAD>
<FRAMESET cols="50%, 50%" title="Our big document">
<FRAME src="main.html" title="Where the content is displayed">
<FRAME src="table_of_contents.html" title="Table of Contents">
<NOFRAMES>
<A href="table_of_contents.html">Table of Contents.</A>
<!-- other navigational links that are available in main.html
are available here also. -->
</NOFRAMES>
</FRAMESET>
</HTML>
</pre>
<p>and the user agent is not displaying frames, the user will have access (via
a link) to a non-frames version of the same information.</p>
<p class="off">End example.</p>
</div>
<h3>10.4 <a id="frame-has-html-src" name="frame-has-html-src">Frame
sources</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-dynamic-source"
class="noxref">6.2</a> Ensure that equivalents for dynamic content are updated
when the dynamic content changes. [Priority 1]</li>
</ul>
<!-- Fix this example -IJ -->
<p>Content developers must provide text equivalents of frames so that their
contents and the relationships between frames make sense. Note that as the
contents of a frame change, so must change any description. This is not
possible if an IMG is inserted directly into a frame. Thus, content developers
should always make the source ("src") of a frame an HTML file. Images may be
inserted into the HTML file and their text alternatives will evolve
correctly.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>A correct frameset document</TITLE>
</HEAD>
<FRAMESET cols="100%" title="Evolving frameset">
<FRAME name="goodframe" src="apples.html" title="Apples">
</FRAMESET>
</HTML>
</pre>
<pre>
<!-- In apples.html -->
<P><IMG src="apples.gif" alt="Apples">
</pre>
<p class="off">End example.</p>
</div>
<p>The following deprecated example should be avoided since it inserts <a
href="#edef-IMG">IMG</a> directly in a frame:</p>
<div class="deprecated-example">
<p><strong>Deprecated example.</strong></p>
<pre>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
<HTML>
<HEAD>
<TITLE>A bad frameset document</TITLE>
</HEAD>
<FRAMESET cols="100%" title="Static frameset">
<FRAME name="badframe"
src="apples.gif" title="Apples">
</FRAMESET>
</HTML>
</pre>
<p>Note that if, for example, a link causes a new image to be inserted into the
frame:</p>
<pre>
<P>Visit a beautiful grove of
<A target="badframe" href="oranges.gif" title="Oranges">oranges</A>
</pre>
<p>the initial title of the frame ("Apples") will no longer match the current
content of the frame ("Oranges").</p>
<p class="off">End example.</p>
</div>
<h3>10.5 <a id="no-new-windows" name="no-new-windows">Using FRAME
targets</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-pop-ups"
class="noxref">10.1</a> Until user agents allow users to turn off spawned
windows, do not cause pop-ups or other windows to appear and do not change the
current window without informing the user. [Priority 2]</li>
</ul>
<p>Content developers should avoid specifying a new window as the target of a
frame with target="_blank".</p>
<h3>10.6 <a id="alt-frames" name="alt-frames">Alternatives to frames</a></h3>
<p>One of the most common uses of frames is to split the user's browser window
into two parts: a navigation window and a content window. As an alternative to
frames, we encourage you to try the following:</p>
<ol>
<li>Create one document for the navigation mechanism (call it "nav.html"). A
separate document means that the navigation mechanism may be shared by more
than one document.</li>
<li>In each document requiring the navigation mechanism, include it at the
bottom of the document with the following (or similar) <a href="#edef-OBJECT">
OBJECT</a> markup:
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<P>
<OBJECT data="nav.html">
Go to the <A href="nav.html">table of contents</A>
</OBJECT>
</pre>
</div>
<p>Putting the navigation mechanism at the end of the document means that when
style sheets are turned off, users have access to the document's important
information first.</p>
</li>
<li>Use style sheets to position the navigation mechanism where you want on the
screen. For example, the following CSS rule floats the navigation bar to the
left of the page and makes it take up 25% of the available horizontal space:
<div class="css-example">
<pre>
OBJECT { float: left; width: 25% }
</pre>
</div>
<p>The following CSS rule attaches the navigation mechanism to the bottom-left
corner of the page of the page and keeps it there even if the user scrolls down
the page:</p>
<div class="css-example">
<pre>
OBJECT { position: fixed; left: 0; bottom: 0 }
</pre>
</div>
</li>
</ol>
<p><strong>Note.</strong> Navigation mechanisms or other content may be
inserted in a document by means of server-side includes.</p>
<h4>10.6.1 <a id="frame-relative-size" name="frame-relative-size">Sizing frames
with relative units</a></h4>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-relative-units"
class="noxref">3.4</a> Use relative rather than absolute units in markup
language attribute values and style sheet property values.
[Priority 2]</li>
</ul>
<p>In the previous examples, note that frame sizes are specified in percentage.
When a user resizes the window, the frames will adjust accordingly and remain
readable.</p>
<h2>11 <a id="forms" name="forms">Forms</a></h2>
<p>This section discusses the accessibility of forms and form controls that one
can put in a <a href="#edef-FORM">FORM</a> element.</p>
<h3>11.1 <a id="forms-keyboard-access" name="forms-keyboard-access">Keyboard
access to forms</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-tab-order" class="noxref">
9.4</a> Create a logical tab order through links, form controls, and objects.
[Priority 3]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-keyboard-shortcuts"
class="noxref">9.5</a> Provide keyboard shortcuts to important links (including
those in client-side image maps), form controls, and groups of form controls.
[Priority 3]</li>
</ul>
<p>In the next example, we specify a tabbing order among elements (in order,
"field2", "field1", "submit") with "<a href="#adef-tabindex">tabindex</a>":</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<FORM action="submit" method="post">
<P>
<INPUT tabindex="2" type="text" name="field1">
<INPUT tabindex="1" type="text" name="field2">
<INPUT tabindex="3" type="submit" name="submit">
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<p>This example assigns "U" as the accesskey (via "<a
href="#adef-accesskey">accesskey</a>"). Typing "U" gives focus to the label,
which in turn gives focus to the input control, so that the user can input
text.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<FORM action="submit" method="post">
<P>
<LABEL for="user" accesskey="U">name</LABEL>
<INPUT type="text" id="user">
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<h3>11.2 <a id="forms-grouping" name="forms-grouping">Grouping form
controls</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-group-information"
class="noxref">12.3</a> Divide large blocks of information into more manageable
groups where natural and appropriate. [Priority 2]</li>
</ul>
<p>Content developers should <a href="#grouping">group information</a> where
natural and appropriate. When form controls can be grouped into logical units,
use the <a href="#edef-FIELDSET">FIELDSET</a> element and label those units
with the <a href="#edef-LEGEND">LEGEND</a> element:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<FORM action="http://example.com/adduser" method="post">
<FIELDSET>
<LEGEND>Personal information</LEGEND>
<LABEL for="firstname">First name: </LABEL>
<INPUT type="text" id="firstname" tabindex="1">
<LABEL for="lastname">Last name: </LABEL>
<INPUT type="text" id="lastname" tabindex="2">
...more personal information...
</FIELDSET>
<FIELDSET>
<LEGEND>Medical History</LEGEND>
...medical history information...
</FIELDSET>
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<h4>11.2.1 <a id="forms-group-options" name="forms-group-options">Grouping menu
options</a></h4>
<p>Content developers should <a href="#grouping">group information</a> where
natural and appropriate. For long lists of menu selections (which may be
difficult to track), content developers should group <a href="#edef-SELECT">
SELECT</a> items (defined by <a href="#edef-OPTION">OPTION</a>) into a
hierarchy using the <a href="#edef-OPTGROUP">OPTGROUP</a> element. Specifies a
label for the group of options with the <a href="#adef-label">label</a>
attribute on OPTGROUP.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<FORM action="http://example.com/prog/someprog" method="post">
<P>
<SELECT name="ComOS">
<OPTGROUP label="PortMaster 3">
<OPTION label="3.7.1" value="pm3_3.7.1">PortMaster 3 with ComOS 3.7.1
<OPTION label="3.7" value="pm3_3.7">PortMaster 3 with ComOS 3.7
<OPTION label="3.5" value="pm3_3.5">PortMaster 3 with ComOS 3.5
</OPTGROUP>
<OPTGROUP label="PortMaster 2">
<OPTION label="3.7" value="pm2_3.7">PortMaster 2 with ComOS 3.7
<OPTION label="3.5" value="pm2_3.5">PortMaster 2 with ComOS 3.5
</OPTGROUP>
<OPTGROUP label="IRX">
<OPTION label="3.7R" value="IRX_3.7R">IRX with ComOS 3.7R
<OPTION label="3.5R" value="IRX_3.5R">IRX with ComOS 3.5R
</OPTGROUP>
</SELECT>
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<h3>11.3 <a id="forms-labels" name="forms-labels">Labeling form
controls</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-associate-labels"
class="noxref">12.4</a> Associate labels explicitly with their controls.
[Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-unassociated-labels"
class="noxref">10.2</a> Until user agents support explicit associations between
labels and form controls, for all form controls with implicitly associated
labels, ensure that the label is properly positioned. [Priority 2]</li>
</ul>
<p>An example of <a href="#edef-LABEL">LABEL</a> used with "<a
href="#adef-for">for</a>" in HTML 4.01 is given in the previous section.</p>
<p>A label is implicitly associated with its form control either through markup
or positioning on the page. The following example shows how a label and form
control may be implicitly associated with markup.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<LABEL for="firstname">First name:
<INPUT type="text" id="firstname" tabindex="1">
</LABEL>
</pre>
<p class="off">End example.</p>
</div>
<h3>11.4 <a id="forms-graphical-buttons" name="forms-graphical-buttons">
Graphical buttons</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
</ul>
<p>Using images to decorate buttons allows developers to make their forms
unique and easier to understand. Using an image for a button (e.g., with the <a
href="#edef-INPUT">INPUT</a> element or <a href="#edef-BUTTON">BUTTON</a>) is
not inherently inaccessible - assuming a text equivalent is provided for the
image.</p>
<p>However, a graphical form submit button created with <a href="#edef-INPUT">
INPUT</a>, type="image" creates a type of server-side image map. Whenever the
button is clicked with a mouse, the x and y coordinates of the mouse click are
sent to the server as part of the form submission.</p>
<p>In the <a href="#images">Image and Image Maps</a> section, we discuss why
server-side images ought to be avoided, and suggest using client-side image
maps instead. In HTML 4.01, graphical buttons may now be client-side image
maps. To preserve the functionality provided by the server, authors have the
following options, as stated in the HTML 4.01 Recommendation (<cite><a
href="#ref-HTML4" title="Link to reference HTML4">[HTML4]</a></cite>, section
17.4.1):</p>
<blockquote>
<p>If the server takes different actions depending on the location clicked,
users of non-graphical browsers will be disadvantaged.<br />
For this reason, authors should consider alternate approaches:</p>
<ul>
<li>Use multiple submit buttons (each with its own image) in place of a single
graphical submit button. Authors may use style sheets to control the
positioning of these buttons.</li>
<li>Use a client-side image map together with scripting.</li>
</ul>
</blockquote>
<h3>11.5 <a id="forms-specific" name="forms-specific">Techniques for specific
controls</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-place-holders"
class="noxref">10.4</a> Until user agents handle empty controls correctly,
include default, place-holding characters in edit boxes and text areas.
[Priority 3]</li>
</ul>
<div class="example">
<p><strong>Example.</strong></p>
<p>Some legacy assistive technologies require initial text in form controls
such as <a href="#edef-TEXTAREA">TEXTAREA</a> in order to function
properly.</p>
<pre>
<FORM action="http://example.com/prog/text-read" method="post">
<P>
<TEXTAREA name=yourname rows="20" cols="80">
Please enter your name here.
</TEXTAREA>
<INPUT type="submit" value="Send"><INPUT type="reset">
</P>
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<p><a id="submit-alt" name="submit-alt">Provide</a> a <a
href="http://www.w3.org/TR/WCAG10-TECHS/#def-text-equivalent">text
equivalent</a> for images used as "submit" buttons:</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<FORM action="http://example.com/prog/text-read" method="post">
<P>
<INPUT type="image" name=submit src="button.gif" alt="Submit">
</FORM>
</pre>
<p class="off">End example.</p>
</div>
<p>Also refer to the section on <a href="#link-accesskey">keyboard access</a>
since this applies to form controls.</p>
<h3>11.6 <a id="bc-forms" name="bc-forms">Backward compatibility issues for
forms</a></h3>
<p>In some HTML 3.2 browsers,</p>
<ul>
<li>The <a href="#edef-BUTTON">BUTTON</a> element does not appear</li>
<li><a href="#edef-INPUT">INPUT</a> with type="button" will appear as a text
input field</li>
</ul>
<h2>12 <a id="scripts" name="scripts">Scripts</a></h2>
<p>This section discusses the accessibility of scripts included in a document
via the <a href="#edef-SCRIPT">SCRIPT</a> element.
<!-- p>@@this section needs work. plus, is this the best place for this
discussion? should we have a separate "non-w3c" module?</p --></p>
<h3>12.1 <a id="scripts-gt" name="scripts-gt">Graceful transformation of
scripts</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-fallback-page"
class="noxref">6.5</a> Ensure that dynamic content is accessible or provide an
alternative presentation or page. [Priority 2]</li>
</ul>
<p>Content developers must ensure that pages are accessible with scripts turned
off or in browsers that don't support scripts.</p>
<ul>
<li>Avoid creating content on the fly on the client. If a user's browser does
not handle scripts, no content will be generated or displayed. However, this is
different than displaying or hiding already existing content by using a
combination of style sheets and scripting; if there is no script, then the
content is always shown. This also does not rule out generating pages on the
fly on the server-side and delivering them to the client.</li>
<li>Avoid creating links that use "javascript" as the URI. If a user is not
using scripts, then they won't be able to link since the browser can't create
the link content.
<div class="deprecated-example">
<p><strong>Deprecated example.</strong> This is a dead-end link for a user
agent where scripts are not supported or not loaded.</p>
<pre>
<A href="javascript:">...</A>
</pre>
<p class="off">End example.</p>
</div>
</li>
</ul>
<h3>12.2 <a id="scripts-flicker" name="scripts-flicker">Scripts that cause
flickering</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-flicker"
class="noxref">7.1</a> Until user agents allow users to control flickering,
avoid causing the screen to flicker. [Priority 1]</li>
</ul>
<!-- p>@@how to create and pause flicker with scripts</p -->
<h3>12.3 <a id="scripts-movement-blinking" name="scripts-movement-blinking">
Scripts that cause movement and blinking</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-blinking"
class="noxref">7.2</a> Until user agents allow users to control blinking, avoid
causing content to blink (i.e., change presentation at a regular rate, such as
turning on and off). [Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-movement"
class="noxref">7.3</a> Until user agents allow users to freeze moving content,
avoid movement in pages. [Priority 2]</li>
</ul>
<!-- p>@@how to create accessible scripts that cause movement and blinking. Part of the
next section? directly accessible scripts?</p -->
<h3>12.4 <a id="directly-accessible-scripts"
name="directly-accessible-scripts">Directly accessible scripts</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-keyboard-operable-scripts"
class="noxref">6.4</a> For scripts and applets, ensure that event handlers are
input device-independent. [Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-scripts" class="noxref">
6.3</a> Ensure that pages are usable when scripts, applets, or other
programmatic objects are turned off or not supported. If this is not possible,
provide equivalent information on an alternative accessible page.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-directly-accessible"
class="noxref">8.1</a> Make programmatic elements such as scripts and applets
directly accessible or compatible with assistive technologies [Priority 1
if functionality is important and not presented elsewhere, otherwise
Priority 2.]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-device-independent-events"
class="noxref">9.3</a> For scripts, specify logical event handlers rather than
device-dependent event handlers. [Priority 2]</li>
</ul>
<p>An event handler is a script that is invoked when a certain event occurs
(e.g, the mouse moves, a key is pressed, the document is loaded, etc.). In HTML
4.01, event handlers are attached to elements via <a
href="#event-handler-attribs">event handler attributes</a> (the attributes
beginning with "on", as in "onkeyup").</p>
<p>Some event handlers, when invoked, produce purely decorative effects such as
highlighting an image or changing the color of an element's text. Other event
handlers produce much more substantial effects, such as carrying out a
calculation, providing important information to the user, or submitting a form.
For event handlers that do more than just change the presentation of an
element, content developers should do the following:</p>
<ol>
<li>Use application-level event triggers rather than user interaction-level
triggers. In HTML 4.01, application-level event attributes are "onfocus",
"onblur" (the opposite of "onfocus"), and "onselect". Note that these
attributes are designed to be device-independent, but are implemented as
keyboard specific events in current browsers.</li>
<li>Otherwise, if you must use device-dependent attributes, provide redundant
input mechanisms (i.e., specify two handlers for the same element):
<ul>
<li>Use "onmousedown" with "onkeydown".</li>
<li>Use "onmouseup" with "onkeyup"</li>
<li>Use "onclick" with "onkeypress"</li>
</ul>
<p>Note that there is no keyboard equivalent to double-clicking ("ondblclick")
in HTML 4.01.</p>
</li>
<li>Do not write event handlers that rely on mouse coordinates since this
prevents device-independent input.</li>
</ol>
<h3>12.5 <a id="scripts-alt" name="scripts-alt">Alternative presentation of
scripts</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent"
class="noxref">1.1</a> Provide a text equivalent for every non-text element
(e.g., via "alt", "longdesc", or in element content). <em>This includes</em>:
images, graphical representations of text (including symbols), image map
regions, animations (e.g., animated GIFs), applets and programmatic objects,
<acronym title="American Standard Code for Information Interchange">
ASCII</acronym> art, frames, scripts, images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video.
[Priority 1]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-dynamic-source"
class="noxref">6.2</a> Ensure that equivalents for dynamic content are updated
when the dynamic content changes. [Priority 1]</li>
</ul>
<p>One way to accomplish this is with the <a href="#edef-NOSCRIPT">NOSCRIPT</a>
element. The content of this element is rendered when scripts are not
enabled.</p>
<div class="example">
<p><strong>Example.</strong></p>
<pre>
<SCRIPT type="text/tcl">
...some Tcl script to show a billboard of sports scores...
</SCRIPT>
<NOSCRIPT>
<P>Results from yesterday's games:</P>
<DL>
<DT>Bulls 91, Sonics 80.
<DD><A href="bullsonic.html">Bulls vs. Sonics game highlights</A>
...more scores...
</DL>
</NOSCRIPT>
</pre>
<p class="off">End example.</p>
</div>
<h3>12.6 <a id="script-refresh" name="script-refresh">Page updates and new
windows</a></h3>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-no-periodic-refresh"
class="noxref">7.4</a> Until user agents provide the ability to stop the
refresh, do not create periodically auto-refreshing pages.
[Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-no-auto-forward"
class="noxref">7.5</a> Until user agents provide the ability to stop
auto-redirect, do not use markup to redirect pages automatically. Instead,
configure the server to perform redirects. [Priority 2]</li>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-pop-ups"
class="noxref">10.1</a> Until user agents allow users to turn off spawned
windows, do not cause pop-ups or other windows to appear and do not change the
current window without informing the user. [Priority 2]</li>
</ul>
<!-- p>@@this section needs work.</p -->
<h2>13 <a id="html-index" name="html-index">Index of HTML elements and
attributes</a></h2>
<p>Checkpoints in this section:</p>
<ul>
<li><a href="http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-deprecated"
class="noxref">11.2</a> Avoid deprecated features of W3C technologies.
[Priority 2]</li>
</ul>
<h3 class="nonb"><a id="index-elements" name="index-elements">Elements</a></h3>
<p><a href="elemidx-linear.html">Linear version of HTML 4.01 element
index</a>.</p>
<p>This index lists all elements in HTML 4.01. The first column of this table
links to the definition of the element in the HTML 4.01 specification (<cite><a
href="#ref-HTML4" title="Link to reference HTML4">[HTML4]</a></cite>). Elements
that are deprecated in HTML 4.01 are followed by an asterisk (*). Elements that
are obsolete in HTML 4.01 or don't exist in a W3C specification of HTML (2.0,
3.2, 4.01) do not appear in this table.</p>
<p>The second column indicates other W3C specifications for HTML that included
each element. The third column indicates the element's role.</p>
<p>The last column lists the sections in the current document where the element
is discussed. An entry of "N/A" means that the element is not discussed in this
document.</p>
<table
summary="Element index. Column heads are element name, defined in versions other than HTML 4.0, role, and relevant techniques"
border="1">
<tr>
<th valign="top" align="left">Element name</th>
<th valign="top" align="left">Defined also in</th>
<th valign="top" align="left">Role</th>
<th valign="top" align="left">Techniques</th>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-A" name="edef-A"
href="http://www.w3.org/TR/html401/struct/links.html#edef-A">A</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-ABBR" name="edef-ABBR"
href="http://www.w3.org/TR/html401/struct/text.html#edef-ABBR">ABBR</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-ACRONYM" name="edef-ACRONYM"
href="http://www.w3.org/TR/html401/struct/text.html#edef-ACRONYM">
ACRONYM</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-ADDRESS" name="edef-ADDRESS"
href="http://www.w3.org/TR/html401/struct/global.html#edef-ADDRESS">
ADDRESS</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-APPLET" name="edef-APPLET"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-APPLET">
APPLET*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Replaced</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-AREA" name="edef-AREA"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-AREA">AREA</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-B" name="edef-B"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-B">B</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BASE" name="edef-BASE"
href="http://www.w3.org/TR/html401/struct/links.html#edef-BASE">BASE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BASEFONT" name="edef-BASEFONT"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-BASEFONT">
BASEFONT*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BDO" name="edef-BDO"
href="http://www.w3.org/TR/html401/struct/dirlang.html#edef-BDO">BDO</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BIG" name="edef-BIG"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-BIG">BIG</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BLOCKQUOTE" name="edef-BLOCKQUOTE"
href="http://www.w3.org/TR/html401/struct/text.html#edef-BLOCKQUOTE">
BLOCKQUOTE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BODY" name="edef-BODY"
href="http://www.w3.org/TR/html401/struct/global.html#edef-BODY">BODY</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BR" name="edef-BR"
href="http://www.w3.org/TR/html401/struct/text.html#edef-BR">BR</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-BUTTON" name="edef-BUTTON"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-BUTTON">
BUTTON</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-CAPTION" name="edef-CAPTION"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-CAPTION">
CAPTION</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-CENTER" name="edef-CENTER"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-CENTER">
CENTER*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-CITE" name="edef-CITE"
href="http://www.w3.org/TR/html401/struct/text.html#edef-CITE">CITE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-CODE" name="edef-CODE"
href="http://www.w3.org/TR/html401/struct/text.html#edef-CODE">CODE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-COL" name="edef-COL"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-COL">COL</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-COLGROUP" name="edef-COLGROUP"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-COLGROUP">
COLGROUP</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DD" name="edef-DD"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-DD">DD</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DEL" name="edef-DEL"
href="http://www.w3.org/TR/html401/struct/text.html#edef-del">DEL</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DFN" name="edef-DFN"
href="http://www.w3.org/TR/html401/struct/text.html#edef-DFN">DFN</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DIR" name="edef-DIR"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-DIR">DIR*</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DIV" name="edef-DIV"
href="http://www.w3.org/TR/html401/struct/global.html#edef-DIV">DIV</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DL" name="edef-DL"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-DL">DL</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-DT" name="edef-DT"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-DT">DT</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-EM" name="edef-EM"
href="http://www.w3.org/TR/html401/struct/text.html#edef-EM">EM</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-FIELDSET" name="edef-FIELDSET"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-FIELDSET">
FIELDSET</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-FONT" name="edef-FONT"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-FONT">
FONT*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-FORM" name="edef-FORM"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-FORM">FORM</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-FRAME" name="edef-FRAME"
href="http://www.w3.org/TR/html401/present/frames.html#edef-FRAME">
FRAME</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Replaced</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-FRAMESET" name="edef-FRAMESET"
href="http://www.w3.org/TR/html401/present/frames.html#edef-FRAMESET">
FRAMESET</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-H1" name="edef-H1"
href="http://www.w3.org/TR/html401/struct/global.html#edef-H1">H1</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-HEAD" name="edef-HEAD"
href="http://www.w3.org/TR/html401/struct/global.html#edef-HEAD">HEAD</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-HR" name="edef-HR"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-HR">HR</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-HTML" name="edef-HTML"
href="http://www.w3.org/TR/html401/struct/global.html#edef-HTML">HTML</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-I" name="edef-I"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-I">I</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-IFRAME" name="edef-IFRAME"
href="http://www.w3.org/TR/html401/present/frames.html#edef-IFRAME">
IFRAME</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Replaced</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-IMG" name="edef-IMG"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-IMG">IMG</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Replaced</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-INPUT" name="edef-INPUT"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-INPUT">
INPUT</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-INS" name="edef-INS"
href="http://www.w3.org/TR/html401/struct/text.html#edef-ins">INS</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-ISINDEX" name="edef-ISINDEX"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-ISINDEX">
ISINDEX*</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-KBD" name="edef-KBD"
href="http://www.w3.org/TR/html401/struct/text.html#edef-KBD">KBD</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-LABEL" name="edef-LABEL"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-LABEL">
LABEL</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-LEGEND" name="edef-LEGEND"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-LEGEND">
LEGEND</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-LI" name="edef-LI"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-LI">LI</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-LINK" name="edef-LINK"
href="http://www.w3.org/TR/html401/struct/links.html#edef-LINK">LINK</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-MAP" name="edef-MAP"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-MAP">MAP</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-MENU" name="edef-MENU"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-MENU">MENU*</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-META" name="edef-META"
href="http://www.w3.org/TR/html401/struct/global.html#edef-META">META</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-NOFRAMES" name="edef-NOFRAMES"
href="http://www.w3.org/TR/html401/present/frames.html#edef-NOFRAMES">
NOFRAMES</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-NOSCRIPT" name="edef-NOSCRIPT"
href="http://www.w3.org/TR/html401/interact/scripts.html#edef-NOSCRIPT">
NOSCRIPT</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-OBJECT" name="edef-OBJECT"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-OBJECT">
OBJECT</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Replaced</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-OL" name="edef-OL"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-OL">OL</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-OPTGROUP" name="edef-OPTGROUP"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-OPTGROUP">
OPTGROUP</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-OPTION" name="edef-OPTION"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-OPTION">
OPTION</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-P" name="edef-P"
href="http://www.w3.org/TR/html401/struct/text.html#edef-P">P</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-PARAM" name="edef-PARAM"
href="http://www.w3.org/TR/html401/struct/objects.html#edef-PARAM">
PARAM</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-PRE" name="edef-PRE"
href="http://www.w3.org/TR/html401/struct/text.html#edef-PRE">PRE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-Q" name="edef-Q"
href="http://www.w3.org/TR/html401/struct/text.html#edef-Q">Q</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-S" name="edef-S"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-S">S*</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SAMP" name="edef-SAMP"
href="http://www.w3.org/TR/html401/struct/text.html#edef-SAMP">SAMP</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SCRIPT" name="edef-SCRIPT"
href="http://www.w3.org/TR/html401/interact/scripts.html#edef-SCRIPT">
SCRIPT</a></td>
<td valign="top" align="left">3.2 (DTD)</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SELECT" name="edef-SELECT"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-SELECT">
SELECT</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SMALL" name="edef-SMALL"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-SMALL">
SMALL</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SPAN" name="edef-SPAN"
href="http://www.w3.org/TR/html401/struct/global.html#edef-SPAN">SPAN</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-STRIKE" name="edef-STRIKE"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-STRIKE">
STRIKE*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-STRONG" name="edef-STRONG"
href="http://www.w3.org/TR/html401/struct/text.html#edef-STRONG">
STRONG</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-STYLE" name="edef-STYLE"
href="http://www.w3.org/TR/html401/present/styles.html#edef-STYLE">
STYLE</a></td>
<td valign="top" align="left">3.2 (DTD)</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SUB" name="edef-SUB"
href="http://www.w3.org/TR/html401/struct/text.html#edef-SUB">SUB</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-SUP" name="edef-SUP"
href="http://www.w3.org/TR/html401/struct/text.html#edef-SUP">SUP</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TABLE" name="edef-TABLE"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TABLE">
TABLE</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TBODY" name="edef-TBODY"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TBODY">
TBODY</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TD" name="edef-TD"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TD">TD</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TEXTAREA" name="edef-TEXTAREA"
href="http://www.w3.org/TR/html401/interact/forms.html#edef-TEXTAREA">
TEXTAREA</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TFOOT" name="edef-TFOOT"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TFOOT">
TFOOT</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TH" name="edef-TH"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TH">TH</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-THEAD" name="edef-THEAD"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-THEAD">
THEAD</a></td>
<td valign="top" align="left"> </td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TITLE" name="edef-TITLE"
href="http://www.w3.org/TR/html401/struct/global.html#edef-TITLE">
TITLE</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TR" name="edef-TR"
href="http://www.w3.org/TR/html401/struct/tables.html#edef-TR">TR</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-TT" name="edef-TT"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-TT">TT</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-U" name="edef-U"
href="http://www.w3.org/TR/html401/present/graphics.html#edef-U">U*</a></td>
<td valign="top" align="left">3.2</td>
<td valign="top" align="left">Presentation</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-UL" name="edef-UL"
href="http://www.w3.org/TR/html401/struct/lists.html#edef-UL">UL</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="edef-VAR" name="edef-VAR"
href="http://www.w3.org/TR/html401/struct/text.html#edef-VAR">VAR</a></td>
<td valign="top" align="left">2.0, 3.2</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
</table>
<h3 class="nonb"><a id="index-attributes"
name="index-attributes">Attributes</a></h3>
<p><a href="attridx-linear.html">Linear version of HTML 4.01 attribute
index</a>.</p>
<p>This index lists some attributes in HTML 4.01 that affect accessibility and
what elements they apply to. The first column of this table links to the
definition of the attribute in the HTML 4.01 specification (<cite><a
href="#ref-HTML4" title="Link to reference HTML4">[HTML4]</a></cite>).
Attributes and elements that are deprecated in HTML 4.01 (<cite><a
href="#ref-HTML4" title="Link to reference HTML4">[HTML4]</a></cite>) are
followed by an asterisk (*). Attributes and elements that are obsolete in HTML
4.01 or don't exist in a W3C specification of HTML (2.0, 3.2, 4.01) do not
appear in this table. Attributes that apply to most elements of HTML 4.01 are
indicated as such; please consult the HTML 4.01 specification for the exact
list of elements with this attribute.</p>
<p>The second column indicates other W3C specifications for HTML that included
each attribute. The third column indicates the elements that take each
attribute. The fourth column indicates the attribute's role.</p>
<p>The last column lists the sections in the current document where the
attribute is discussed. An entry of "N/A" means that the attribute is not
discussed in this document.</p>
<table
summary="Attribute index. Column heads are attribute name, applies to elements, role, and relevant techniques"
border="1">
<tr>
<th valign="top" align="left">Attribute name</th>
<th valign="top" align="left">Applies to elements</th>
<th valign="top" align="left">Role</th>
<th valign="top" align="left">Techniques</th>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-abbr" name="adef-abbr"
href="http://www.w3.org/TR/html401/struct/tables.html#adef-abbr">abbr</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-TD">TD</a>, <a
href="elemidx-linear.html#edef-TH">TH</a></td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-accesskey" name="adef-accesskey"
href="http://www.w3.org/TR/html401/interact/forms.html#adef-accesskey">
accesskey</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-A">A</a>, <a
href="elemidx-linear.html#edef-AREA">AREA</a>, <a
href="elemidx-linear.html#edef-BUTTON">BUTTON</a>, <a
href="elemidx-linear.html#edef-INPUT">INPUT</a>, <a
href="elemidx-linear.html#edef-LABEL">LABEL</a>, <a
href="elemidx-linear.html#edef-LEGEND">LEGEND</a>, <a
href="elemidx-linear.html#edef-TEXTAREA">TEXTAREA</a></td>
<td valign="top" align="left">User Interface</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-alt" name="adef-alt"
href="http://www.w3.org/TR/html401/struct/objects.html#adef-alt">alt</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-APPLET">
APPLET</a>, <a href="elemidx-linear.html#edef-AREA">AREA</a>, <a
href="elemidx-linear.html#edef-IMG">IMG</a>, <a
href="elemidx-linear.html#edef-INPUT">INPUT</a></td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-axis" name="adef-axis"
href="http://www.w3.org/TR/html401/struct/tables.html#adef-axis">axis</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-TD">TD</a>, <a
href="elemidx-linear.html#edef-TH">TH</a></td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-class" name="adef-class"
href="http://www.w3.org/TR/html401/struct/global.html#adef-class">
class</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-dir" name="adef-dir"
href="http://www.w3.org/TR/html401/struct/dirlang.html#adef-dir">dir</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-for" name="adef-for"
href="http://www.w3.org/TR/html401/interact/forms.html#adef-for">for</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-LABEL">
LABEL</a></td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-headers" name="adef-headers"
href="http://www.w3.org/TR/html401/struct/tables.html#adef-headers">
headers</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-TD">TD</a>, <a
href="elemidx-linear.html#edef-TH">TH</a></td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-hreflang" name="adef-hreflang"
href="http://www.w3.org/TR/html401/struct/links.html#adef-hreflang">
hreflang</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-A">A</a>, <a
href="elemidx-linear.html#edef-LINK">LINK</a></td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-id" name="adef-id"
href="http://www.w3.org/TR/html401/struct/global.html#adef-id">id</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-label" name="adef-label"
href="http://www.w3.org/TR/html401/interact/forms.html#adef-label-OPTION">
label</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-OPTION">
OPTION</a></td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-lang" name="adef-lang"
href="http://www.w3.org/TR/html401/struct/dirlang.html#adef-lang">lang</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-longdesc" name="adef-longdesc"
href="http://www.w3.org/TR/html401/struct/objects.html#adef-longdesc-IMG">
longdesc</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-IMG">IMG</a>,
<a href="elemidx-linear.html#edef-FRAME">FRAME</a>, <a
href="elemidx-linear.html#edef-IFRAME">IFRAME</a></td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-scope" name="adef-scope"
href="http://www.w3.org/TR/html401/struct/tables.html#adef-scope">
scope</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-TD">TD</a>, <a
href="elemidx-linear.html#edef-TH">TH</a></td>
<td valign="top" align="left">Structure</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-style" name="adef-style"
href="http://www.w3.org/TR/html401/present/styles#adef-style">style</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-summary" name="adef-summary"
href="http://www.w3.org/TR/html401/struct/tables.html#adef-summary">
summary</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-TABLE">
TABLE</a></td>
<td valign="top" align="left">Alternative</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-tabindex" name="adef-tabindex"
href="http://www.w3.org/TR/html401/interact/forms.html#adef-tabindex">
tabindex</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-A">A</a>, <a
href="elemidx-linear.html#edef-AREA">AREA</a>, <a
href="elemidx-linear.html#edef-BUTTON">BUTTON</a>, <a
href="elemidx-linear.html#edef-INPUT">INPUT</a>, <a
href="elemidx-linear.html#edef-OBJECT">OBJECT</a>, <a
href="elemidx-linear.html#edef-SELECT">SELECT</a>, <a
href="elemidx-linear.html#edef-TEXTAREA">TEXTAREA</a></td>
<td valign="top" align="left">User Interface</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-title" name="adef-title"
href="http://www.w3.org/TR/html401/struct/global.html#adef-title">
title</a></td>
<td valign="top" align="left">Most elements</td>
<td valign="top" align="left">Metadata</td>
<td valign="top" align="left">N/A</td>
</tr>
<tr>
<td valign="top" align="left"><a id="adef-usemap" name="adef-usemap"
href="http://www.w3.org/TR/html401/struct/objects.html#adef-usemap">
usemap</a></td>
<td valign="top" align="left"><a href="elemidx-linear.html#edef-IMG">IMG</a>,
<a href="elemidx-linear.html#edef-INPUT">INPUT</a>, <a
href="elemidx-linear.html#edef-OBJECT">OBJECT</a></td>
<td valign="top" align="left">Processing</td>
<td valign="top" align="left">N/A</td>
</tr>
</table>
<p>The following is the list of HTML 4.01 attributes not directly related to
accessibility. Content developers should use style sheets instead of
presentation attributes. For event handler attributes, please refer to the
section on <a href="#directly-accessible-scripts">device-independent event
handlers</a> for more detail.</p>
<dl>
<dt><b>Other structural attributes:</b></dt>
<dd>start*, value*, rowspan, colspan, span</dd>
<dt><b>Other presentation attributes:</b></dt>
<dd>align*, valign*, clear*, nowrap*, char, charoff, hspace*, vspace*,
cellpadding, cellspacing, compact*, face*, size*, background*, bgcolor*,
color*, text*, link*, alink*, vlink*, border, noshade*, rules, size (deprecated
according to element), marginheight, marginwidth, frame, frameborder, rows,
cols</dd>
<dt><b>Other processing instruction attributes:</b></dt>
<dd><a id="adef-ismap" name="adef-ismap">ismap</a>, coords, <a id="adef-shape"
name="adef-shape">shape</a></dd>
<dt><b>Other user interface attributes:</b></dt>
<dd>target, scrolling, noresize</dd>
<dt><b>Other metadata attributes:</b></dt>
<dd><a id="adef-type" name="adef-type">type</a>, cite, datetime</dd>
<dt><b><a id="event-handler-attribs" name="event-handler-attribs">Event handler
attributes:</a></b></dt>
<dd>onblur, onchange, onclick, ondblclick, onfocus, onkeydown, onkeypress,
onkeyup, onload, onload, onmousedown, onmousemove, onmouseout, onmouseover,
onmouseup, onreset, onselect, onsubmit, onunload</dd>
</dl>
<hr />
<!--NewPage--><!-- this is for html2ps -->
<h2>14 <a id="References" name="References">References</a></h2>
<p>For the latest version of any <abbr title="the World Wide Web Consortium">
W3C</abbr> specification please consult the list of <a
href="http://www.w3.org/TR/"><abbr title="the World Wide Web Consortium">
W3C</abbr> Technical Reports</a> at http://www.w3.org/TR.</p>
<dl>
<dt><a id="ref-CSS1" name="ref-CSS1"><b>[CSS1]</b></a></dt>
<dd><a href="http://www.w3.org/TR/1999/REC-CSS1-19990111">"CSS, level 1
Recommendation"</a>, B. Bos, H. Wium Lie, eds., 17 December 1996, revised 11
January 1999. This CSS1 Recommendation is
http://www.w3.org/TR/1999/REC-CSS1-19990111. The <a
href="http://www.w3.org/TR/REC-CSS1">latest version of CSS1</a> is available at
http://www.w3.org/TR/REC-CSS1.</dd>
<dt><a id="ref-CSS2" name="ref-CSS2"><b>[CSS2]</b></a></dt>
<dd><a href="http://www.w3.org/TR/1998/REC-CSS2-19980512/">"CSS, level 2
Recommendation"</a>, B. Bos, H. Wium Lie, C. Lilley, and I. Jacobs, eds., 12
May 1998. This CSS2 Recommendation is
http://www.w3.org/TR/1998/REC-CSS2-19980512/. The <a
href="http://www.w3.org/TR/REC-CSS2/">latest version of CSS2</a> is available
at http://www.w3.org/TR/REC-CSS2.</dd>
<dt><a id="ref-HTML4" name="ref-HTML4"><b>[HTML4]</b></a></dt>
<dd><a href="http://www.w3.org/TR/1999/REC-html401-19991224/">"HTML 4.01
Recommendation"</a>, D. Raggett, A. Le Hors, and I. Jacobs, eds., 24 December
1999. This <acronym>HTML</acronym> 4.01 Recommendation is
http://www.w3.org/TR/1999/REC-html401-19991224/.</dd>
<dt><a id="ref-MATHML" name="ref-MATHML"><b>[MATHML]</b></a></dt>
<dd><a href="http://www.w3.org/1999/07/REC-MathML-19990707/">"Mathematical
Markup Language"</a>, P. Ion and R. Miner, eds., 7 April 1998, revised 7 July
1999. This MathML 1.0 Recommendation is
http://www.w3.org/TR/1998/REC-MathML-19990707/. The <a
href="http://www.w3.org/TR/REC-MathML/">latest version of MathML 1.0</a> is
available at http://www.w3.org/TR/REC-MathML.</dd>
<dt><a id="ref-WCAG10" name="ref-WCAG10"><b>[WCAG10]</b></a></dt>
<dd><a href="http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/">"Web Content
Accessibility Guidelines 1.0"</a>, W. Chisholm, G. Vanderheiden, and I. Jacobs,
eds., 5 May 1999. This <acronym>WCAG</acronym> 1.0 Recommendation is
http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/.</dd>
<dt><a id="ref-WCAG10-CSS-TECHNIQUES" name="ref-WCAG10-CSS-TECHNIQUES"><b>
[WCAG10-CSS-TECHNIQUES]</b></a></dt>
<dd><a href="http://www.w3.org/TR/WCAG10-CSS-TECHS/">"CSS Techniques for Web
Content Accessibility Guidelines 1.0"</a>, W. Chisholm, G. Vanderheiden, and I.
Jacobs, eds. The latest version of this document is available at
http://www.w3.org/TR/WCAG10-CSS-TECHS/.</dd>
<dt><a id="ref-WCAG10-TECHS" name="ref-WCAG10-TECHS"><b>
[WCAG10-TECHS]</b></a></dt>
<dd><a href="http://www.w3.org/TR/WCAG10-TECHS/">"Techniques for Web Content
Accessibility Guidelines 1.0"</a>, W. Chisholm, G. Vanderheiden, I. Jacobs,
eds. This document explains how to implement the checkpoints defined in "Web
Content Accessibility Guidelines 1.0". The latest draft of the techniques is
available at http://www.w3.org/TR/WCAG10-TECHS/.</dd>
</dl>
<h2>15 <a id="Resources" name="Resources">Resources</a></h2>
<p><strong>Note:</strong> <em>W3C does not guarantee the stability of any of
the following references outside of its control. These references are included
for convenience. References to products are not endorsements of those
products.</em></p>
<h3>15.1 <a id="OtherGuidelines" name="OtherGuidelines">Other
guidelines</a></h3>
<dl>
<dt><a id="ref-IBMJAVA" name="ref-IBMJAVA"><b>[IBMJAVA]</b></a></dt>
<dd><a href="http://www-3.ibm.com/able/access.html">IBM Guidelines for Writing
Accessible Applications Using 100% Pure Java</a> are available from IBM Special
Needs Systems.</dd>
<dt><a id="ref-JAVAACCESS" name="ref-JAVAACCESS"><b>[JAVAACCESS]</b></a></dt>
<dd>Information about <a href="http://trace.wisc.edu/world/java/java.htm">Java
Accessibility and Usability</a> is available from the Trace R&D
Center.</dd>
<dt><a id="ref-MACROMEDIA" name="ref-MACROMEDIA"><b>[MACROMEDIA]</b></a></dt>
<dd><a href="http://www.macromedia.com/support/flash/ts/documents/tn4150.html">
Flash OBJECT and EMBED Tag Syntax</a> from Macromedia.</dd>
<dt><a id="ref-UWSAG" name="ref-UWSAG"><b>[UWSAG]</b></a></dt>
<dd><a href="http://trace.wisc.edu/redirects/htmlgide/version8.htm">"The
Unified Web Site Accessibility Guidelines"</a>, G. Vanderheiden, W. Chisholm,
eds. The Unified Web Site Guidelines were compiled by the <a
href="http://www.tracecenter.org/">Trace R & D Center</a> at the University
of Wisconsin under funding from the National Institute on Disability and
Rehabilitation Research (NIDRR), U.S. Dept. of Education.</dd>
</dl>
<h3>15.2 <a id="ToolResources" name="ToolResources">User agents and other
tools</a></h3>
<p>A list of <a href="http://www.w3.org/WAI/References/Browsing">alternative
Web browsers</a> (assistive technologies and other user agents designed for
accessibility) is maintained at the WAI Web site.</p>
<dl>
<dt><a id="ref-ASTER" name="ref-ASTER"><b>[ASTER]</b></a></dt>
<dd>For information about ASTER, an "Audio System For Technical Readings",
consult <a href="http://www.cs.cornell.edu/home/raman/">T. V. Raman's home
page</a>.</dd>
<dt><a id="ref-HYPERMEDIA" name="ref-HYPERMEDIA"><b>[HYPERMEDIA]</b></a></dt>
<dd><a href="http://www-4.ibm.com/software/network/techexplorer/">IBM's
techexplorer Hypermedia Browser</a>.</dd>
</dl>
<h3>15.3 <a id="AccessResources" name="AccessResources">Accessibility
resources</a></h3>
<dl>
<dt><a id="ref-TRACE" name="ref-TRACE"><b>[TRACE]</b></a></dt>
<dd>The <a href="http://trace.wisc.edu/">Trace Research & Development
Center</a>. Consult this site for a variety of information about accessibility,
including a <a href="http://trace.wisc.edu/world/java/ScrollText.java">
scrolling Java applet that may be frozen by the user</a>.</dd>
<dt><a id="ref-WAI-ER" name="ref-WAI-ER"><b>[WAI-ER]</b></a></dt>
<dd>The <a href="http://www.w3.org/WAI/ER/">WAI Evaluation and Repair Working
Group</a></dd>
</dl>
<!--NewPage--><!-- this is for html2ps -->
<h2>16 <a id="Acknowledgments" name="Acknowledgments">Acknowledgments</a></h2>
<dl>
<dt>Web Content Guidelines Working Group Co-Chairs:</dt>
<dd><a href="mailto:jasonw@ariel.ucs.unimelb.edu.au">Jason White</a>,
University of Melbourne</dd>
<dd><a href="mailto:gv@tracecenter.org">Gregg Vanderheiden</a>, Trace Research
and Development</dd>
<dt>W3C Team contact:</dt>
<dd><a href="mailto:wendy@w3.org">Wendy Chisholm</a></dd>
<dt>We wish to thank the following people who have contributed their time and
valuable comments to shaping these guidelines:</dt>
<dd>Harvey Bingham, Kevin Carey, Chetz Colwell, Neal Ewers, Geoff Freed, Al
Gilman, Larry Goldberg, Jon Gunderson, Eric Hansen, Phill Jenkins, Leonard
Kasday, George Kerscher, Marja-Riitta Koivunen, Josh Krieger, Chuck Letourneau,
Scott Luebking, William Loughborough, Murray Maloney, Charles McCathieNevile,
MegaZone (Livingston Enterprises), Masafumi Nakane, Mark Novak, Charles
Oppermann, Mike Paciello, David Pawson, Michael Pieper, Greg Rosmaita, Liam
Quinn, Dave Raggett, T.V. Raman, Robert Savellis, Jutta Treviranus, Steve
Tyler, and Jaap van Lelieveld</dd>
</dl>
<p><a href="http://www.w3.org/WAI/WCAG1AAA-Conformance"
title="Explanation of Level Triple-A Conformance"><img class="conform"
height="32" width="88" src="http://www.w3.org/WAI/wcag1AAA"
alt="Level Triple-A conformance icon, W3C-WAI Web Content Accessibility Guidelines 1.0" />
</a></p>
<div class="navbar"><map id="navbar-bottom" name="navbar-bottom"
title="Navigation Bar">
<hr class="navbar" title="Navigation area separator" />
<p>[<a href="#toc">contents</a>] [<a href="#html-index">html index</a>]
</p>
</map></div>
</body>
</html>