discontinued / server · Files

index.html 127 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 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">

<html lang=en>
 <head>
  <title>Selectors Level 3</title>
  <link href=default.css rel=stylesheet type="text/css">
  <link href="http://www.w3.org/StyleSheets/TR/W3C-REC.css" rel=stylesheet
  type="text/css">

 <body>
  <div class=head> <!--begin-logo-->
   <p><a href="http://www.w3.org/"><img alt=W3C height=48
    src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->

   <h1 id=title>Selectors Level 3</h1>

   <h2 class="no-num no-toc" id=longstatus-date>W3C Recommendation
    29 September 2011</h2>

   <dl>
    <dt>This version:

    <dd> <a href="http://www.w3.org/TR/2011/REC-css3-selectors-20110929/">
     http://www.w3.org/TR/2011/REC-css3-selectors-20110929/</a>
     <!-- <a href="http://dev.w3.org/csswg/selectors3">
             http://dev.w3.org/csswg/selectors3</a> -->
     
     <dt>Latest version:

    <dd><a href="http://www.w3.org/TR/css3-selectors/">
     http://www.w3.org/TR/css3-selectors/</a>
     
    <dt>Latest Selectors specification:

    <dd><a href="http://www.w3.org/TR/selectors/">
     http://www.w3.org/TR/selectors/</a>

    <dt>Previous version:

    <dd> <a href="http://www.w3.org/TR/2009/PR-css3-selectors-20091215/">
     http://www.w3.org/TR/2009/PR-css3-selectors-20091215/</a>

    <dt><a name=editors-list></a>Editors:

    <dd class=vcard><a class="url fn" href="http://www.tantek.com/"
     lang=tr>Tantek &Ccedil;elik</a> (Invited Expert)

    <dd class=vcard><a class="url fn"
     href="http://fantasai.inkedblade.net/contact">Elika J. Etemad</a>
     (Invited Expert)

    <dd class=vcard><span class=fn>Daniel Glazman</span> (Disruptive
     Innovations SARL)

    <dd class=vcard><a class="url fn" href="mailto:ian@hixie.ch">Ian
     Hickson</a> (<span class=company><a
     href="http://www.google.com/">Google</a></span>)

    <dd class=vcard><span class=fn>Peter Linss</span> (former editor, <span
     class=company><a
     href="http://www.netscape.com/">Netscape/AOL</a></span>)

    <dd class=vcard><span class=fn>John Williams</span> (former editor, <span
     class=company><a href="http://www.quark.com/">Quark, Inc.</a></span>)
   </dl>
   
   <p>Please refer to the <a href="http://www.w3.org/Style/2011/REC-css3-selectors-20110929-errata.html"><strong>errata</strong></a> for this document, which may include some normative corrections.</p>
   
   <p>See also <a href="http://www.w3.org/2003/03/Translations/byTechnology?technology=css3-selectors"> <strong>translations</strong></a>.</p>
   
   <!--begin-copyright-->
<p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> &copy; 2011 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>&reg;</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></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> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p>
   <!--end-copyright-->
   <hr title="Separator for header">
  </div>

  <h2 class="no-num no-toc" id=abstract>Abstract</h2>

  <p><em>Selectors</em> are patterns that match against elements in a tree,
   and as such form one of several technologies that can be used to select
   nodes in an XML document. Selectors have been optimized for use with HTML
   and XML, and are designed to be usable in performance-critical code.

  <p><acronym title="Cascading Style Sheets">CSS</acronym> (Cascading Style
   Sheets) is a language for describing the rendering of <acronym
   title="Hypertext Markup Language">HTML</acronym> and <acronym
   title="Extensible Markup Language">XML</acronym> documents on screen, on
   paper, in speech, etc. CSS uses Selectors for binding style properties to
   elements in the document.

  <p>This document describes the selectors that already exist in <abbr
   title="CSS level 1">CSS1</abbr> <a href="#CSS1"
   rel=biblioentry>[CSS1]<!--{{CSS1}}--></a> and <abbr title="CSS level
   2">CSS2</abbr> <a href="#CSS21"
   rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>, and further introduces new
   selectors for <abbr title="CSS level 3">CSS3</abbr> and other languages
   that may need them.

  <p>Selectors define the following function:

  <pre>expression &#x2217; element &rarr; boolean</pre>

  <p>That is, given an element and a selector, this specification defines
   whether that element matches the selector.

  <p>These expressions can also be used, for instance, to select a set of
   elements, or a single element from a set of elements, by evaluating the
   expression across all the elements in a subtree. <acronym title="Simple
   Tree Transformation Sheets">STTS</acronym> (Simple Tree Transformation
   Sheets), a language for transforming XML trees, uses this mechanism. <a
   href="#STTS3" rel=biblioentry>[STTS3]<!--{{STTS3}}--></a>

  <h2 class="no-num no-toc" id=status>Status of this document</h2>
  <!--begin-status-->

  <p><em>This section describes the status of this document at the time of
   its publication. Other documents may supersede this document. A list of
   current W3C publications and the latest revision of this technical report
   can be found in the <a href="http://www.w3.org/TR/">W3C technical reports
   index at http://www.w3.org/TR/.</a></em>

  <p>This document was produced by the <a
   href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> as a <a
   href="http://www.w3.org/Consortium/Process/tr#RecsPR">Proposed
   Recommendation.</a>

  <p>A W3C Recommendation is a mature document that has been widely
   reviewed and has been shown to be implementable. W3C encourages everybody
   to implement this specification. Comments may be sent to the (<a
   href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
   mailing list <a
   href="mailto:www-style@w3.org?Subject=%5Bcss3-selectors%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>
   (see <a href="http://www.w3.org/Mail/Request">instructions</a>). When
   sending e-mail, please put the text &#8220;css3-selectors&#8221; in the
   subject, preferably like this: &#8220;[<!---->css3-selectors<!---->]
   <em>&hellip;summary of comment&hellip;</em>&#8221;

<p>This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.</p>

  <p>This document was produced by a group operating under the <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5&nbsp;February
   2004 W3C Patent Policy</a>. W3C maintains a <a
   href="http://www.w3.org/2004/01/pp-impl/32061/status"
   rel=disclosure>public list of any patent disclosures</a> made in
   connection with the deliverables of the group; that page also includes
   instructions for disclosing a patent. An individual who has actual
   knowledge of a patent which the individual believes contains <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
   Claim(s)</a> must disclose the information in accordance with <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">
   section&nbsp;6 of the W3C Patent Policy</a>.</p>
  <!--end-status-->

  <p>A separate <a
   href="/Style/CSS/Test/CSS3/Selectors/20091025/reports/CR-ImpReport.html">
   implementation report</a> contains a test suite and shows several
   implementations of the specification.

  <p id=changes>This document is the same as the previous, Proposed Recommendation
   version, except for editorial changes to the front matter, and updating of references.


  <h2 class="no-num no-toc" id=contents>Table of Contents</h2>
  <!--begin-toc-->

  <ul class=toc>
   <li><a href="#context"><span class=secno>1. </span>Introduction</a>
    <ul class=toc>
     <li><a href="#dependencies"><span class=secno>1.1.
      </span>Dependencies</a>

     <li><a href="#terminology"><span class=secno>1.2. </span>Terminology</a>
      

     <li><a href="#changesFromCSS2"><span class=secno>1.3. </span>Changes
      from CSS2</a>
    </ul>

   <li><a href="#selectors"><span class=secno>2. </span>Selectors</a>

   <li><a href="#casesens"><span class=secno>3. </span>Case sensitivity</a>

   <li><a href="#selector-syntax"><span class=secno>4. </span>Selector
    syntax</a>

   <li><a href="#grouping"><span class=secno>5. </span>Groups of
    selectors</a>

   <li><a href="#simple-selectors"><span class=secno>6. </span>Simple
    selectors</a>
    <ul class=toc>
     <li><a href="#type-selectors"><span class=secno>6.1. </span>Type
      selector</a>
      <ul class=toc>
       <li><a href="#typenmsp"><span class=secno>6.1.1. </span>Type selectors
        and namespaces</a>
      </ul>

     <li><a href="#universal-selector"><span class=secno>6.2.
      </span>Universal selector </a>
      <ul class=toc>
       <li><a href="#univnmsp"><span class=secno>6.2.1. </span>Universal
        selector and namespaces</a>
      </ul>

     <li><a href="#attribute-selectors"><span class=secno>6.3.
      </span>Attribute selectors</a>
      <ul class=toc>
       <li><a href="#attribute-representation"><span class=secno>6.3.1.
        </span>Attribute presence and value selectors</a>

       <li><a href="#attribute-substrings"><span class=secno>6.3.2.
        </span>Substring matching attribute selectors</a>

       <li><a href="#attrnmsp"><span class=secno>6.3.3. </span>Attribute
        selectors and namespaces</a>

       <li><a href="#def-values"><span class=secno>6.3.4. </span>Default
        attribute values in DTDs</a>
      </ul>

     <li><a href="#class-html"><span class=secno>6.4. </span>Class
      selectors</a>

     <li><a href="#id-selectors"><span class=secno>6.5. </span>ID
      selectors</a>

     <li><a href="#pseudo-classes"><span class=secno>6.6.
      </span>Pseudo-classes</a>
      <ul class=toc>
       <li><a href="#dynamic-pseudos"><span class=secno>6.6.1. </span>Dynamic
        pseudo-classes</a>
        <ul class=toc>
         <li><a href="#the-link-pseudo-classes-link-and-visited"><span
          class=secno>6.6.1.1. </span>The link pseudo-classes: :link and
          :visited</a>

         <li><a href="#the-user-action-pseudo-classes-hover-act"><span
          class=secno>6.6.1.2. </span>The user action pseudo-classes :hover,
          :active, and :focus</a>
        </ul>

       <li><a href="#target-pseudo"><span class=secno>6.6.2. </span>The
        target pseudo-class :target</a>

       <li><a href="#lang-pseudo"><span class=secno>6.6.3. </span>The
        language pseudo-class :lang</a>

       <li><a href="#UIstates"><span class=secno>6.6.4. </span>The UI element
        states pseudo-classes</a>
        <ul class=toc>
         <li><a href="#enableddisabled"><span class=secno>6.6.4.1. </span>The
          :enabled and :disabled pseudo-classes</a>

         <li><a href="#checked"><span class=secno>6.6.4.2. </span>The
          :checked pseudo-class</a>

         <li><a href="#indeterminate"><span class=secno>6.6.4.3. </span>The
          :indeterminate pseudo-class</a>
        </ul>

       <li><a href="#structural-pseudos"><span class=secno>6.6.5.
        </span>Structural pseudo-classes</a>
        <ul class=toc>
         <li><a href="#root-pseudo"><span class=secno>6.6.5.1. </span>:root
          pseudo-class</a>

         <li><a href="#nth-child-pseudo"><span class=secno>6.6.5.2.
          </span>:nth-child() pseudo-class</a>

         <li><a href="#nth-last-child-pseudo"><span class=secno>6.6.5.3.
          </span>:nth-last-child() pseudo-class</a>

         <li><a href="#nth-of-type-pseudo"><span class=secno>6.6.5.4.
          </span>:nth-of-type() pseudo-class</a>

         <li><a href="#nth-last-of-type-pseudo"><span class=secno>6.6.5.5.
          </span>:nth-last-of-type() pseudo-class</a>

         <li><a href="#first-child-pseudo"><span class=secno>6.6.5.6.
          </span>:first-child pseudo-class</a>

         <li><a href="#last-child-pseudo"><span class=secno>6.6.5.7.
          </span>:last-child pseudo-class</a>

         <li><a href="#first-of-type-pseudo"><span class=secno>6.6.5.8.
          </span>:first-of-type pseudo-class</a>

         <li><a href="#last-of-type-pseudo"><span class=secno>6.6.5.9.
          </span>:last-of-type pseudo-class</a>

         <li><a href="#only-child-pseudo"><span class=secno>6.6.5.10.
          </span>:only-child pseudo-class</a>

         <li><a href="#only-of-type-pseudo"><span class=secno>6.6.5.11.
          </span>:only-of-type pseudo-class</a>

         <li><a href="#empty-pseudo"><span class=secno>6.6.5.12.
          </span>:empty pseudo-class</a>
        </ul>

       <li><a href="#content-selectors"><span class=secno>6.6.6.
        </span>Blank</a>

       <li><a href="#negation"><span class=secno>6.6.7. </span>The negation
        pseudo-class</a>
      </ul>
    </ul>

   <li><a href="#pseudo-elements"><span class=secno>7.
    </span>Pseudo-elements</a>
    <ul class=toc>
     <li><a href="#first-line"><span class=secno>7.1. </span>The ::first-line
      pseudo-element</a>
      <ul class=toc>
       <li><a href="#first-formatted-line"><span class=secno>7.1.1.
        </span>First formatted line definition in CSS</a>
      </ul>

     <li><a href="#first-letter"><span class=secno>7.2. </span>The
      ::first-letter pseudo-element</a>
      <ul class=toc>
       <li><a href="#application-in-css"><span class=secno>7.2.1.
        </span>Application in CSS</a>
      </ul>

     <li><a href="#selection"><span class=secno>7.3. </span>Blank</a>

     <li><a href="#gen-content"><span class=secno>7.4. </span>The ::before
      and ::after pseudo-elements</a>
    </ul>

   <li><a href="#combinators"><span class=secno>8. </span>Combinators</a>
    <ul class=toc>
     <li><a href="#descendant-combinators"><span class=secno>8.1.
      </span>Descendant combinator</a>

     <li><a href="#child-combinators"><span class=secno>8.2. </span>Child
      combinators</a>

     <li><a href="#sibling-combinators"><span class=secno>8.3. </span>Sibling
      combinators</a>
      <ul class=toc>
       <li><a href="#adjacent-sibling-combinators"><span class=secno>8.3.1.
        </span>Adjacent sibling combinator</a>

       <li><a href="#general-sibling-combinators"><span class=secno>8.3.2.
        </span>General sibling combinator</a>
      </ul>
    </ul>

   <li><a href="#specificity"><span class=secno>9. </span>Calculating a
    selector's specificity</a>

   <li><a href="#w3cselgrammar"><span class=secno>10. </span>The grammar of
    Selectors</a>
    <ul class=toc>
     <li><a href="#grammar"><span class=secno>10.1. </span>Grammar</a>

     <li><a href="#lex"><span class=secno>10.2. </span>Lexical scanner</a>
    </ul>

   <li><a href="#profiling"><span class=secno>11. </span>Profiles</a>

   <li><a href="#Conformance"><span class=secno>12. </span>Conformance and
    requirements</a>

   <li><a href="#Tests"><span class=secno>13. </span>Tests</a>

   <li><a href="#ACKS"><span class=secno>14. </span>Acknowledgements</a>

   <li><a href="#references"><span class=secno>15. </span>References</a>
    <ul class=toc>
     <li><a href="#normative-references"><span class=secno>15.1.
      </span>Normative References</a>

     <li><a href="#informative-references"><span class=secno>15.2.
      </span>Informative References</a>
    </ul>
  </ul>
  <!--end-toc-->

  <h2 id=context><span class=secno>1. </span>Introduction</h2>

  <p>Selectors Level 1 and Selectors Level 2 are defined as the subsets of
   selector functionality defined in the <a
   href="http://www.w3.org/TR/REC-CSS1">CSS1</a> and <a
   href="http://www.w3.org/TR/CSS21/">CSS2.1</a> specifications,
   respectively.

  <h3 id=dependencies><span class=secno>1.1. </span>Dependencies</h3>

  <p>Some features of this specification are specific to CSS, or have
   particular limitations or rules specific to CSS. In this specification,
   these have been described in terms of CSS2.1. <a href="#CSS21"
   rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>

  <h3 id=terminology><span class=secno>1.2. </span>Terminology</h3>

  <p>All of the text of this specification is normative except examples,
   notes, and sections explicitly marked as non-normative.

  <p>Additional terminology is defined in the <a
   href="http://www.w3.org/TR/CSS21/conform.html#defs">Definitions</a>
   section of <a href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>.
   Examples of document source code and fragments are given in XML [[XML10]
   or HTML [[HTML40]] syntax.

  <h3 id=changesFromCSS2><span class=secno>1.3. </span>Changes from CSS2</h3>

  <p><em>This section is non-normative.</em>

  <p>The main differences between the selectors in CSS2 and those in
   Selectors are:

  <ul>
   <li>the list of basic definitions (selector, group of selectors, simple
    selector, etc.) has been changed; in particular, what was referred to in
    CSS2 as a simple selector is now called a sequence of simple selectors,
    and the term "simple selector" is now used for the components of this
    sequence

   <li>an optional namespace component is now allowed in element type
    selectors, the universal selector and attribute selectors

   <li>a <a href="#general-sibling-combinators">new combinator</a> has been
    introduced

   <li>new simple selectors including substring matching attribute selectors,
    and new pseudo-classes

   <li>new pseudo-elements, and introduction of the "::" convention for
    pseudo-elements

   <li>the grammar has been rewritten

   <li>profiles to be added to specifications integrating Selectors and
    defining the set of selectors which is actually supported by each
    specification

   <li>Selectors are now a CSS3 Module and an independent specification;
    other specifications can now refer to this document independently of CSS

   <li>the specification now has its own test suite
  </ul>

  <h2 id=selectors><span class=secno>2. </span>Selectors</h2>

  <p><em>This section is non-normative, as it merely summarizes the following
   sections.</em>

  <p>A Selector represents a structure. This structure can be used as a
   condition (e.g. in a CSS rule) that determines which elements a selector
   matches in the document tree, or as a flat description of the HTML or XML
   fragment corresponding to that structure.

  <p>Selectors may range from simple element names to rich contextual
   representations.

  <p>The following table summarizes the Selector syntax:

  <table class=selectorsReview>
   <thead>
    <tr>
     <th class=pattern>Pattern

     <th class=meaning>Meaning

     <th class=described>Described in section

     <th class=origin>First defined in CSS level

   <tbody>
    <tr>
     <td class=pattern>*

     <td class=meaning>any element

     <td class=described><a href="#universal-selector">Universal selector</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E

     <td class=meaning>an element of type E

     <td class=described><a href="#type-selectors">Type selector</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E[foo]

     <td class=meaning>an E element with a "foo" attribute

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E[foo="bar"]

     <td class=meaning>an E element whose "foo" attribute value is exactly
      equal to "bar"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E[foo~="bar"]

     <td class=meaning>an E element whose "foo" attribute value is a list of
      whitespace-separated values, one of which is exactly equal to "bar"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E[foo^="bar"]

     <td class=meaning>an E element whose "foo" attribute value begins
      exactly with the string "bar"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E[foo$="bar"]

     <td class=meaning>an E element whose "foo" attribute value ends exactly
      with the string "bar"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E[foo*="bar"]

     <td class=meaning>an E element whose "foo" attribute value contains the
      substring "bar"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E[foo|="en"]

     <td class=meaning>an E element whose "foo" attribute has a
      hyphen-separated list of values beginning (from the left) with "en"

     <td class=described><a href="#attribute-selectors">Attribute
      selectors</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E:root

     <td class=meaning>an E element, root of the document

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:nth-child(n)

     <td class=meaning>an E element, the n-th child of its parent

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:nth-last-child(n)

     <td class=meaning>an E element, the n-th child of its parent, counting
      from the last one

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:nth-of-type(n)

     <td class=meaning>an E element, the n-th sibling of its type

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:nth-last-of-type(n)

     <td class=meaning>an E element, the n-th sibling of its type, counting
      from the last one

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:first-child

     <td class=meaning>an E element, first child of its parent

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E:last-child

     <td class=meaning>an E element, last child of its parent

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:first-of-type

     <td class=meaning>an E element, first sibling of its type

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:last-of-type

     <td class=meaning>an E element, last sibling of its type

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:only-child

     <td class=meaning>an E element, only child of its parent

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:only-of-type

     <td class=meaning>an E element, only sibling of its type

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:empty

     <td class=meaning>an E element that has no children (including text
      nodes)

     <td class=described><a href="#structural-pseudos">Structural
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:link<br>
      E:visited

     <td class=meaning>an E element being the source anchor of a hyperlink of
      which the target is not yet visited (:link) or already visited
      (:visited)

     <td class=described><a href="#link">The link pseudo-classes</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E:active<br>
      E:hover<br>
      E:focus

     <td class=meaning>an E element during certain user actions

     <td class=described><a href="#useraction-pseudos">The user action
      pseudo-classes</a>

     <td class=origin>1 and 2

    <tr>
     <td class=pattern>E:target

     <td class=meaning>an E element being the target of the referring URI

     <td class=described><a href="#target-pseudo">The target pseudo-class</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:lang(fr)

     <td class=meaning>an element of type E in language "fr" (the document
      language specifies how language is determined)

     <td class=described><a href="#lang-pseudo">The :lang() pseudo-class</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E:enabled<br>
      E:disabled

     <td class=meaning>a user interface element E which is enabled or
      disabled

     <td class=described><a href="#UIstates">The UI element states
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E:checked<!--<br>E:indeterminate-->

     <td class=meaning>a user interface element E which is
      checked<!-- or in an
      indeterminate state--> (for instance a
      radio-button or checkbox)

     <td class=described><a href="#UIstates">The UI element states
      pseudo-classes</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E::first-line

     <td class=meaning>the first formatted line of an E element

     <td class=described><a href="#first-line">The ::first-line
      pseudo-element</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E::first-letter

     <td class=meaning>the first formatted letter of an E element

     <td class=described><a href="#first-letter">The ::first-letter
      pseudo-element</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E::before

     <td class=meaning>generated content before an E element

     <td class=described><a href="#gen-content">The ::before
      pseudo-element</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E::after

     <td class=meaning>generated content after an E element

     <td class=described><a href="#gen-content">The ::after
      pseudo-element</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E.warning

     <td class=meaning>an E element whose class is "warning" (the document
      language specifies how class is determined).

     <td class=described><a href="#class-html">Class selectors</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E#myid

     <td class=meaning>an E element with ID equal to "myid".

     <td class=described><a href="#id-selectors">ID selectors</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E:not(s)

     <td class=meaning>an E element that does not match simple selector s

     <td class=described><a href="#negation">Negation pseudo-class</a>

     <td class=origin>3

    <tr>
     <td class=pattern>E F

     <td class=meaning>an F element descendant of an E element

     <td class=described><a href="#descendant-combinators">Descendant
      combinator</a>

     <td class=origin>1

    <tr>
     <td class=pattern>E &gt; F

     <td class=meaning>an F element child of an E element

     <td class=described><a href="#child-combinators">Child combinator</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E + F

     <td class=meaning>an F element immediately preceded by an E element

     <td class=described><a href="#adjacent-sibling-combinators">Adjacent
      sibling combinator</a>

     <td class=origin>2

    <tr>
     <td class=pattern>E ~ F

     <td class=meaning>an F element preceded by an E element

     <td class=described><a href="#general-sibling-combinators">General
      sibling combinator</a>

     <td class=origin>3
  </table>

  <p>The meaning of each selector is derived from the table above by
   prepending "matches" to the contents of each cell in the "Meaning" column.

  <h2 id=casesens><span class=secno>3. </span>Case sensitivity</h2>

  <p>All Selectors syntax is case-insensitive within the ASCII range (i.e.
   [a-z] and [A-Z] are equivalent), except for parts that are not under the
   control of Selectors. The case sensitivity of document language element
   names, attribute names, and attribute values in selectors depends on the
   document language. For example, in HTML, element names are
   case-insensitive, but in XML, they are case-sensitive. Case sensitivity of
   namespace prefixes is defined in <a href="#CSS3NAMESPACE"
   rel=biblioentry>[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>.

  <h2 id=selector-syntax><span class=secno>4. </span>Selector syntax</h2>

  <p>A <dfn id=selector>selector</dfn> is a chain of one or more <a
   href="#sequence">sequences of simple selectors</a> separated by <a
   href="#combinators">combinators</a>. One <a
   href="#pseudo-elements">pseudo-element</a> may be appended to the last
   sequence of simple selectors in a selector.

  <p>A <dfn id=sequence-of-simple-selectors><a name=sequence>sequence of
   simple selectors</a></dfn> is a chain of <a
   href="#simple-selectors-dfn">simple selectors</a> that are not separated
   by a <a href="#combinators">combinator</a>. It always begins with a <a
   href="#type-selectors">type selector</a> or a <a
   href="#universal-selector">universal selector</a>. No other type selector
   or universal selector is allowed in the sequence.

  <p>A <dfn id=simple-selector><a name=simple-selectors-dfn></a><a
   href="#simple-selectors">simple selector</a></dfn> is either a <a
   href="#type-selectors">type selector</a>, <a
   href="#universal-selector">universal selector</a>, <a
   href="#attribute-selectors">attribute selector</a>, <a
   href="#class-html">class selector</a>, <a href="#id-selectors">ID
   selector</a>, or <a href="#pseudo-classes">pseudo-class</a>.

  <p><dfn id=combinators0>Combinators</dfn> are: whitespace,
   &quot;greater-than sign&quot; (U+003E, <code>&gt;</code>), &quot;plus
   sign&quot; (U+002B, <code>+</code>) and &quot;tilde&quot; (U+007E,
   <code>~</code>). White space may appear between a combinator and the
   simple selectors around it. <a name=whitespace></a>Only the characters
   "space" (U+0020), "tab" (U+0009), "line feed" (U+000A), "carriage return"
   (U+000D), and "form feed" (U+000C) can occur in whitespace. Other
   space-like characters, such as "em-space" (U+2003) and "ideographic space"
   (U+3000), are never part of whitespace.

  <p>The elements of a document tree that are represented by a selector are
   the <dfn id=subjects-of-the-selector><a name=subject></a>subjects of the
   selector</dfn>. A selector consisting of a single sequence of simple
   selectors represents any element satisfying its requirements. Prepending
   another sequence of simple selectors and a combinator to a sequence
   imposes additional matching constraints, so the subjects of a selector are
   always a subset of the elements represented by the last sequence of simple
   selectors.

  <p>An empty selector, containing no sequence of simple selectors and no
   pseudo-element, is an <a href="#Conformance">invalid selector</a>.

  <p>Characters in Selectors can be escaped with a backslash according to the
   same <a href="http://www.w3.org/TR/CSS21/syndata.html#characters">escaping
   rules</a> as CSS. <a href="#CSS21"
   rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>.

  <p id=nsdecl>Certain selectors support namespace prefixes. The mechanism by
   which namespace prefixes are <dfn id=declared>declared</dfn> should be
   specified by the language that uses Selectors. If the language does not
   specify a namespace prefix declaration mechanism, then no prefixes are
   declared. In CSS, namespace prefixes are declared with the <a
   href="http://www.w3.org/TR/css3-namespace/#declaration"><code>@namespace</code></a>
   rule. <a href="#CSS3NAMESPACE"
   rel=biblioentry>[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>

  <h2 id=grouping><span class=secno>5. </span>Groups of selectors</h2>

  <p>A comma-separated list of selectors represents the union of all elements
   selected by each of the individual selectors in the list. (A comma is
   U+002C.) For example, in CSS when several selectors share the same
   declarations, they may be grouped into a comma-separated list. White space
   may appear before and/or after the comma.

  <div class=example>
   <p>CSS example:</p>

   <p>In this example, we condense three rules with identical declarations
    into one. Thus,</p>

   <pre>h1 { font-family: sans-serif }
h2 { font-family: sans-serif }
h3 { font-family: sans-serif }</pre>

   <p>is equivalent to:</p>

   <pre>h1, h2, h3 { font-family: sans-serif }</pre>
  </div>

  <p><strong>Warning</strong>: the equivalence is true in this example
   because all the selectors are valid selectors. If just one of these
   selectors were invalid, the entire group of selectors would be invalid.
   This would invalidate the rule for all three heading elements, whereas in
   the former case only one of the three individual heading rules would be
   invalidated.

  <div class=example>
   <p>Invalid CSS example:</p>

   <pre>h1 { font-family: sans-serif }
h2..foo { font-family: sans-serif }
h3 { font-family: sans-serif }</pre>

   <p>is not equivalent to:</p>

   <pre>h1, h2..foo, h3 { font-family: sans-serif }</pre>

   <p>because the above selector (<code>h1, h2..foo, h3</code>) is entirely
    invalid and the entire style rule is dropped. (When the selectors are not
    grouped, only the rule for <code>h2..foo</code> is dropped.)</p>
  </div>

  <h2 id=simple-selectors><span class=secno>6. </span>Simple selectors</h2>

  <h3 id=type-selectors><span class=secno>6.1. </span>Type selector</h3>

  <p>A <dfn id=type-selector>type selector</dfn> is the name of a document
   language element type written using the syntax of <a
   href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified
   names</a> <a href="#CSS3NAMESPACE"
   rel=biblioentry>[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>. A type
   selector represents an instance of the element type in the document tree.

  <div class=example>
   <p>Example:</p>

   <p>The following selector represents an <code>h1</code> element in the
    document tree:</p>

   <pre>h1</pre>
  </div>

  <h4 id=typenmsp><span class=secno>6.1.1. </span>Type selectors and
   namespaces</h4>

  <p>Type selectors allow an optional namespace component: a namespace prefix
   that has been previously <a href="#nsdecl">declared</a> may be prepended
   to the element name separated by the namespace separator &quot;vertical
   bar&quot; (U+007C, <code>|</code>). (See, e.g., <a href="#XML-NAMES"
   rel=biblioentry>[XML-NAMES]<!--{{XML-NAMES}}--></a> for the use of
   namespaces in XML.)

  <p>The namespace component may be left empty (no prefix before the
   namespace separator) to indicate that the selector is only to represent
   elements with no namespace.

  <p>An asterisk may be used for the namespace prefix, indicating that the
   selector represents elements in any namespace (including elements with no
   namespace).

  <p>Element type selectors that have no namespace component (no namespace
   separator) represent elements without regard to the element's namespace
   (equivalent to "<code>*|</code>") unless a default namespace has been <a
   href="#nsdecl">declared</a> for namespaced selectors (e.g. in CSS, in the
   style sheet). If a default namespace has been declared, such selectors
   will represent only elements in the default namespace.

  <p>A type selector containing a namespace prefix that has not been
   previously <a href="#nsdecl">declared</a> for namespaced selectors is an
   <a href="#Conformance">invalid</a> selector.

  <p>In a namespace-aware client, the name part of element type selectors
   (the part after the namespace separator, if it is present) will only match
   against the <a
   href="http://www.w3.org/TR/REC-xml-names/#NT-LocalPart">local part</a> of
   the element's <a
   href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">qualified
   name</a>.

  <p>In summary:

  <dl>
   <dt><code>ns|E</code>

   <dd>elements with name E in namespace ns

   <dt><code>*|E</code>

   <dd>elements with name E in any namespace, including those without a
    namespace

   <dt><code>|E</code>

   <dd>elements with name E without a namespace

   <dt><code>E</code>

   <dd>if no default namespace has been <a href="#nsdecl">declared</a> for
    selectors, this is equivalent to *|E. Otherwise it is equivalent to ns|E
    where ns is the default namespace.
  </dl>

  <div class=example>
   <p>CSS examples:</p>

   <pre>@namespace foo url(http://www.example.com);
 foo|h1 { color: blue }  /* first rule */
 foo|* { color: yellow } /* second rule */
 |h1 { color: red }      /* ...*/
 *|h1 { color: green }
 h1 { color: green }</pre>

   <p>The first rule (not counting the <code>@namespace</code> at-rule) will
    match only <code>h1</code> elements in the "http://www.example.com"
    namespace.</p>

   <p>The second rule will match all elements in the "http://www.example.com"
    namespace.</p>

   <p>The third rule will match only <code>h1</code> elements with no
    namespace.</p>

   <p>The fourth rule will match <code>h1</code> elements in any namespace
    (including those without any namespace).</p>

   <p>The last rule is equivalent to the fourth rule because no default
    namespace has been defined.</p>
  </div>

  <h3 id=universal-selector><span class=secno>6.2. </span>Universal selector</h3>

  <p>The <dfn id=universal-selector0>universal selector</dfn>, written as a
   <a href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified
   name</a> <a href="#CSS3NAMESPACE"
   rel=biblioentry>[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a> with an
   asterisk (<code>*</code> U+002A) as the local name, represents the
   qualified name of any element type. It represents any single element in
   the document tree in any namespace (including those without a namespace)
   if no default namespace has been specified for selectors. If a default
   namespace has been specified, see <a href="#univnmsp">Universal selector
   and Namespaces</a> below.

  <p>If a universal selector represented by <code>*</code> (i.e. without a
   namespace prefix) is not the only component of a <a
   href="#sequence">sequence of simple selectors</a> selectors or is
   immediately followed by a <a href="#pseudo-elements">pseudo-element</a>,
   then the <code>*</code> may be omitted and the universal selector's
   presence implied.

  <div class=example>
   <p>Examples:</p>

   <ul>
    <li><code>*[hreflang|=en]</code> and <code>[hreflang|=en]</code> are
     equivalent,

    <li><code>*.warning</code> and <code>.warning</code> are equivalent,

    <li><code>*#myid</code> and <code>#myid</code> are equivalent.
   </ul>
  </div>

  <p class=note><strong>Note:</strong> it is recommended that the
   <code>*</code> not be omitted, because it decreases the potential
   confusion between, for example, <code style="white-space: nowrap">div
   :first-child</code> and <code style="white-space:
   nowrap">div:first-child</code>. Here, <code style="white-space:
   nowrap">div *:first-child</code> is more readable.

  <h4 id=univnmsp><span class=secno>6.2.1. </span>Universal selector and
   namespaces</h4>

  <p>The universal selector allows an optional namespace component. It is
   used as follows:

  <dl>
   <dt><code>ns|*</code>

   <dd>all elements in namespace ns

   <dt><code>*|*</code>

   <dd>all elements

   <dt><code>|*</code>

   <dd>all elements without a namespace

   <dt><code>*</code>

   <dd>if no default namespace has been specified, this is equivalent to *|*.
    Otherwise it is equivalent to ns|* where ns is the default namespace.
  </dl>

  <p>A universal selector containing a namespace prefix that has not been
   previously <a href="#nsdecl">declared</a> is an <a
   href="#Conformance">invalid</a> selector.

  <h3 id=attribute-selectors><span class=secno>6.3. </span>Attribute
   selectors</h3>

  <p>Selectors allow the representation of an element's attributes. When a
   selector is used as an expression to match against an element, attribute
   selectors must be considered to match an element if that element has an
   attribute that matches the attribute represented by the attribute
   selector.

  <h4 id=attribute-representation><span class=secno>6.3.1. </span>Attribute
   presence and value selectors</h4>

  <p>CSS2 introduced four attribute selectors:

  <dl>
   <dt><code>[att]</code>

   <dd>Represents an element with the <code>att</code> attribute, whatever
    the value of the attribute.

   <dt><code>[att=val]</code>

   <dd>Represents an element with the <code>att</code> attribute whose value
    is exactly "val".

   <dt><code>[att~=val]</code>

   <dd>Represents an element with the <code>att</code> attribute whose value
    is a <a href="#whitespace">whitespace</a>-separated list of words, one of
    which is exactly "val". If "val" contains whitespace, it will never
    represent anything (since the words are <em>separated</em> by spaces).
    Also if "val" is the empty string, it will never represent anything.

   <dt><code>[att|=val]</code>

   <dd>Represents an element with the <code>att</code> attribute, its value
    either being exactly "val" or beginning with "val" immediately followed
    by "-" (U+002D). This is primarily intended to allow language subcode
    matches (e.g., the <code>hreflang</code> attribute on the <code>a</code>
    element in HTML) as described in BCP 47 (<a href="#BCP47"
    rel=biblioentry>[BCP47]<!--{{BCP47}}--></a>) or its successor. For
    <code>lang</code> (or <code>xml:lang</code>) language subcode matching,
    please see <a href="#lang-pseudo">the <code>:lang</code>
    pseudo-class</a>.
  </dl>

  <p>Attribute values must be CSS <a
   href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>
   or <a href="http://www.w3.org/TR/CSS21/syndata.html#strings">strings</a>.
   <a href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a> The
   case-sensitivity of attribute names and values in selectors depends on the
   document language.

  <div class=example>
   <p>Examples:</p>

   <p>The following attribute selector represents an <code>h1</code> element
    that carries the <code>title</code> attribute, whatever its value:</p>

   <pre>h1[title]</pre>

   <p>In the following example, the selector represents a <code>span</code>
    element whose <code>class</code> attribute has exactly the value
    "example":</p>

   <pre>span[class="example"]</pre>

   <p>Multiple attribute selectors can be used to represent several
    attributes of an element, or several conditions on the same attribute.
    Here, the selector represents a <code>span</code> element whose
    <code>hello</code> attribute has exactly the value "Cleveland" and whose
    <code>goodbye</code> attribute has exactly the value "Columbus":</p>

   <pre>span[hello="Cleveland"][goodbye="Columbus"]</pre>

   <p>The following CSS rules illustrate the differences between "=" and
    "~=". The first selector would match, for example, an <code>a</code>
    element with the value "copyright copyleft copyeditor" on a
    <code>rel</code> attribute. The second selector would only match an
    <code>a</code> element with an <code>href</code> attribute having the
    exact value "http://www.w3.org/".</p>

   <pre>a[rel~="copyright"] { ... }
a[href="http://www.w3.org/"] { ... }</pre>

   <p>The following selector represents an <code>a</code> element whose
    <code>hreflang</code> attribute is exactly "fr".</p>

   <pre>a[hreflang=fr]</pre>

   <p>The following selector represents an <code>a</code> element for which
    the value of the <code>hreflang</code> attribute begins with "en",
    including "en", "en-US", and "en-scouse":</p>

   <pre>a[hreflang|="en"]</pre>

   <p>The following selectors represent a <code>DIALOGUE</code> element
    whenever it has one of two different values for an attribute
    <code>character</code>:</p>

   <pre>DIALOGUE[character=romeo]
DIALOGUE[character=juliet]</pre>
  </div>

  <h4 id=attribute-substrings><span class=secno>6.3.2. </span>Substring
   matching attribute selectors</h4>

  <p>Three additional attribute selectors are provided for matching
   substrings in the value of an attribute:

  <dl>
   <dt><code>[att^=val]</code>

   <dd>Represents an element with the <code>att</code> attribute whose value
    begins with the prefix "val". If "val" is the empty string then the
    selector does not represent anything.

   <dt><code>[att$=val]</code>

   <dd>Represents an element with the <code>att</code> attribute whose value
    ends with the suffix "val". If "val" is the empty string then the
    selector does not represent anything.

   <dt><code>[att*=val]</code>

   <dd>Represents an element with the <code>att</code> attribute whose value
    contains at least one instance of the substring "val". If "val" is the
    empty string then the selector does not represent anything.
  </dl>

  <p>Attribute values must be CSS <a
   href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>
   or <a href="http://www.w3.org/TR/CSS21/syndata.html#strings">strings</a>.
   <a href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a> The
   case-sensitivity of attribute names in selectors depends on the document
   language.

  <div class=example>
   <p>Examples:</p>

   <p>The following selector represents an HTML <code>object</code>,
    referencing an image:</p>

   <pre>object[type^="image/"]</pre>

   <p>The following selector represents an HTML anchor <code>a</code> with an
    <code>href</code> attribute whose value ends with ".html".</p>

   <pre>a[href$=".html"]</pre>

   <p>The following selector represents an HTML paragraph with a
    <code>title</code> attribute whose value contains the substring "hello"</p>

   <pre>p[title*="hello"]</pre>
  </div>

  <h4 id=attrnmsp><span class=secno>6.3.3. </span>Attribute selectors and
   namespaces</h4>

  <p>The attribute name in an attribute selector is given as a <a
   href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS qualified
   name</a>: a namespace prefix that has been previously <a
   href="#nsdecl">declared</a> may be prepended to the attribute name
   separated by the namespace separator &quot;vertical bar&quot;
   (<code>|</code>). In keeping with the Namespaces in the XML
   recommendation, default namespaces do not apply to attributes, therefore
   attribute selectors without a namespace component apply only to attributes
   that have no namespace (equivalent to "<code>|attr</code>"; these
   attributes are said to be in the "per-element-type namespace partition").
   An asterisk may be used for the namespace prefix indicating that the
   selector is to match all attribute names without regard to the attribute's
   namespace.

  <p>An attribute selector with an attribute name containing a namespace
   prefix that has not been previously <a href="#nsdecl">declared</a> is an
   <a href="#Conformance">invalid</a> selector.

  <div class=example>
   <p>CSS examples:</p>

   <pre>@namespace foo "http://www.example.com";
[foo|att=val] { color: blue }
[*|att] { color: yellow }
[|att] { color: green }
[att] { color: green }</pre>

   <p>The first rule will match only elements with the attribute
    <code>att</code> in the "http://www.example.com" namespace with the value
    "val".</p>

   <p>The second rule will match only elements with the attribute
    <code>att</code> regardless of the namespace of the attribute (including
    no namespace).</p>

   <p>The last two rules are equivalent and will match only elements with the
    attribute <code>att</code> where the attribute is not in a namespace.</p>
  </div>

  <h4 id=def-values><span class=secno>6.3.4. </span>Default attribute values
   in DTDs</h4>

  <p>Attribute selectors represent attribute values in the document tree. How
   that document tree is constructed is outside the scope of Selectors. In
   some document formats default attribute values can be defined in a DTD or
   elsewhere, but these can only be selected by attribute selectors if they
   appear in the document tree. Selectors should be designed so that they
   work whether or not the default values are included in the document tree.

  <p>For example, a XML UA may, but is <em>not</em> required to read an
   "external subset" of the DTD but <em>is</em> required to look for default
   attribute values in the document's "internal subset." (See, e.g., <a
   href="#XML10" rel=biblioentry>[XML10]<!--{{XML10}}--></a> for definitions
   of these subsets.) Depending on the UA, a default attribute value defined
   in the external subset of the DTD might or might not appear in the
   document tree.

  <p>A UA that recognizes an XML namespace may, but is not required to use
   its knowledge of that namespace to treat default attribute values as if
   they were present in the document. (For example, an XHTML UA is not
   required to use its built-in knowledge of the XHTML DTD. See, e.g., <a
   href="#XML-NAMES" rel=biblioentry>[XML-NAMES]<!--{{XML-NAMES}}--></a> for
   details on namespaces in XML 1.0.)

  <p class=note><strong>Note:</strong> Typically, implementations choose to
   ignore external subsets. This corresponds to the behaviour of
   non-validating processors as defined by the XML specification.

  <div class=example>
   <p>Example:</p>

   <p>Consider an element <code>EXAMPLE</code> with an attribute
    <code>radix</code> that has a default value of <code>"decimal"</code>.
    The DTD fragment might be</p>

   <pre
    class=dtd-example>&lt;!ATTLIST EXAMPLE radix (decimal,octal) "decimal"></pre>

   <p>If the style sheet contains the rules</p>

   <pre>EXAMPLE[radix=decimal] { /*... default property settings ...*/ }
EXAMPLE[radix=octal]   { /*... other settings...*/ }</pre>

   <p>the first rule might not match elements whose <code>radix</code>
    attribute is set by default, i.e. not set explicitly. To catch all cases,
    the attribute selector for the default value must be dropped:</p>

   <pre>EXAMPLE                { /*... default property settings ...*/ }
EXAMPLE[radix=octal]   { /*... other settings...*/ }</pre>

   <p>Here, because the selector <code>EXAMPLE[radix=octal]</code> is more
    specific than the type selector alone, the style declarations in the
    second rule will override those in the first for elements that have a
    <code>radix</code> attribute value of <code>"octal"</code>. Care has to
    be taken that all property declarations that are to apply only to the
    default case are overridden in the non-default cases' style rules.</p>
  </div>

  <h3 id=class-html><span class=secno>6.4. </span>Class selectors</h3>

  <p>Working with HTML, authors may use the "period" notation (also known as
   "full stop", U+002E, <code>.</code>) as an alternative to the
   <code>~=</code> notation when representing the <code>class</code>
   attribute. Thus, for HTML, <code>div.value</code> and
   <code>div[class~=value]</code> have the same meaning. The attribute value
   must immediately follow the full stop (<code>.</code>).

  <p>UAs may apply selectors using the period (.) notation in XML documents
   if the UA has namespace-specific knowledge that allows it to determine
   which attribute is the "class" attribute for the respective namespace. One
   such example of namespace-specific knowledge is the prose in the
   specification for a particular namespace (e.g. SVG 1.0 <a href="#SVG11"
   rel=biblioentry>[SVG11]<!--{{SVG11}}--></a> describes the <a
   href="http://www.w3.org/TR/2001/PR-SVG-20010719/styling.html#ClassAttribute">SVG
   <code>class</code> attribute</a> and how a UA should interpret it, and
   similarly MathML 1.01 <a href="#MATHML"
   rel=biblioentry>[MATHML]<!--{{MATHML}}--></a> describes the <a
   href="http://www.w3.org/1999/07/REC-MathML-19990707/chapter2.html#sec2.3.4">MathML
   <code>class</code> attribute</a>.)

  <div class=example>
   <p>CSS examples:</p>

   <p>We can assign style information to all elements with
    <code>class~="pastoral"</code> as follows:</p>

   <pre>*.pastoral { color: green }  /* all elements with class~=pastoral */</pre>

   <p>or just</p>

   <pre>.pastoral { color: green }  /* all elements with class~=pastoral */</pre>

   <p>The following assigns style only to H1 elements with
    <code>class~="pastoral"</code>:</p>

   <pre>H1.pastoral { color: green }  /* H1 elements with class~=pastoral */</pre>

   <p>Given these rules, the first <code>H1</code> instance below would not
    have green text, while the second would:</p>

   <pre>&lt;H1&gt;Not green&lt;/H1&gt;
&lt;H1 class="pastoral"&gt;Very green&lt;/H1&gt;</pre>

   <p>The following rule matches any <code>P</code> element whose
    <code>class</code> attribute has been assigned a list of <a
    href="#whitespace">whitespace</a>-separated values that includes both
    <code>pastoral</code> and <code>marine</code>:</p>

   <pre>p.pastoral.marine { color: green }</pre>

   <p>This rule matches when <code>class="pastoral blue aqua marine"</code>
    but does not match for <code>class="pastoral blue"</code>.</p>
  </div>

  <p class=note><strong>Note:</strong> Because CSS gives considerable power
   to the "class" attribute, authors could conceivably design their own
   "document language" based on elements with almost no associated
   presentation (such as <code>DIV</code> and <code>SPAN</code> in HTML) and
   assigning style information through the "class" attribute. Authors should
   avoid this practice since the structural elements of a document language
   often have recognized and accepted meanings and author-defined classes may
   not.

  <p class=note><strong>Note:</strong> If an element has multiple class
   attributes, their values must be concatenated with spaces between the
   values before searching for the class. As of this time the working group
   is not aware of any manner in which this situation can be reached,
   however, so this behavior is explicitly non-normative in this
   specification.

  <h3 id=id-selectors><span class=secno>6.5. </span>ID selectors</h3>

  <p>Document languages may contain attributes that are declared to be of
   type ID. What makes attributes of type ID special is that no two such
   attributes can have the same value in a conformant document, regardless of
   the type of the elements that carry them; whatever the document language,
   an ID typed attribute can be used to uniquely identify its element. In
   HTML all ID attributes are named "id"; XML applications may name ID
   attributes differently, but the same restriction applies.

  <p>An ID-typed attribute of a document language allows authors to assign an
   identifier to one element instance in the document tree. An ID selector
   contains a &quot;number sign&quot; (U+0023, <code>#</code>) immediately
   followed by the ID value, which must be an CSS <a
   href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>.
   An ID selector represents an element instance that has an identifier that
   matches the identifier in the ID selector.

  <p>Selectors does not specify how a UA knows the ID-typed attribute of an
   element. The UA may, e.g., read a document's DTD, have the information
   hard-coded or ask the user.

  <div class=example>
   <p>Examples:</p>

   <p>The following ID selector represents an <code>h1</code> element whose
    ID-typed attribute has the value "chapter1":</p>

   <pre>h1#chapter1</pre>

   <p>The following ID selector represents any element whose ID-typed
    attribute has the value "chapter1":</p>

   <pre>#chapter1</pre>

   <p>The following selector represents any element whose ID-typed attribute
    has the value "z98y".</p>

   <pre>*#z98y</pre>
  </div>

  <p class=note><strong>Note:</strong> In XML 1.0 <a href="#XML10"
   rel=biblioentry>[XML10]<!--{{XML10}}--></a>, the information about which
   attribute contains an element's IDs is contained in a DTD or a schema.
   When parsing XML, UAs do not always read the DTD, and thus may not know
   what the ID of an element is (though a UA may have namespace-specific
   knowledge that allows it to determine which attribute is the ID attribute
   for that namespace). If a style sheet author knows or suspects that a UA
   may not know what the ID of an element is, he should use normal attribute
   selectors instead: <code>[name=p371]</code> instead of <code>#p371</code>.

  <p>If an element has multiple ID attributes, all of them must be treated as
   IDs for that element for the purposes of the ID selector. Such a situation
   could be reached using mixtures of xml:id, DOM3 Core, XML DTDs, and
   namespace-specific knowledge.

  <h3 id=pseudo-classes><span class=secno>6.6. </span>Pseudo-classes</h3>

  <p>The pseudo-class concept is introduced to permit selection based on
   information that lies outside of the document tree or that cannot be
   expressed using the other simple selectors.

  <p>A pseudo-class always consists of a &quot;colon&quot; (<code>:</code>)
   followed by the name of the pseudo-class and optionally by a value between
   parentheses.

  <p>Pseudo-classes are allowed in all sequences of simple selectors
   contained in a selector. Pseudo-classes are allowed anywhere in sequences
   of simple selectors, after the leading type selector or universal selector
   (possibly omitted). Pseudo-class names are case-insensitive. Some
   pseudo-classes are mutually exclusive, while others can be applied
   simultaneously to the same element. Pseudo-classes may be dynamic, in the
   sense that an element may acquire or lose a pseudo-class while a user
   interacts with the document.

  <h4 id=dynamic-pseudos><span class=secno>6.6.1. </span>Dynamic
   pseudo-classes</h4>

  <p>Dynamic pseudo-classes classify elements on characteristics other than
   their name, attributes, or content, in principle characteristics that
   cannot be deduced from the document tree.

  <p>Dynamic pseudo-classes do not appear in the document source or document
   tree.

  <h5 id=the-link-pseudo-classes-link-and-visited><span class=secno>6.6.1.1.
   </span>The <a name=link>link pseudo-classes: :link and :visited</a></h5>

  <p>User agents commonly display unvisited links differently from previously
   visited ones. Selectors provides the pseudo-classes <code>:link</code> and
   <code>:visited</code> to distinguish them:

  <ul>
   <li>The <code>:link</code> pseudo-class applies to links that have not yet
    been visited.

   <li>The <code>:visited</code> pseudo-class applies once the link has been
    visited by the user.
  </ul>

  <p>After some amount of time, user agents may choose to return a visited
   link to the (unvisited) &lsquo;<code class=css>:link</code>&rsquo; state.

  <p>The two states are mutually exclusive.

  <div class=example>
   <p>Example:</p>

   <p>The following selector represents links carrying class
    <code>external</code> and already visited:</p>

   <pre>a.external:visited</pre>
  </div>

  <p class=note><strong>Note:</strong> It is possible for style sheet authors
   to abuse the :link and :visited pseudo-classes to determine which sites a
   user has visited without the user's consent.

  <p>UAs may therefore treat all links as unvisited links, or implement other
   measures to preserve the user's privacy while rendering visited and
   unvisited links differently.

  <h5 id=the-user-action-pseudo-classes-hover-act><span class=secno>6.6.1.2.
   </span>The <a name=useraction-pseudos>user action pseudo-classes :hover,
   :active, and :focus</a></h5>

  <p>Interactive user agents sometimes change the rendering in response to
   user actions. Selectors provides three pseudo-classes for the selection of
   an element the user is acting on.

  <ul>
   <li>The <code>:hover</code> pseudo-class applies while the user designates
    an element with a pointing device, but does not necessarily activate it.
    For example, a visual user agent could apply this pseudo-class when the
    cursor (mouse pointer) hovers over a box generated by the element. User
    agents not that do not support <a
    href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">interactive
    media</a> do not have to support this pseudo-class. Some conforming user
    agents that support <a
    href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">interactive
    media</a> may not be able to support this pseudo-class (e.g., a pen
    device that does not detect hovering).

   <li>The <code>:active</code> pseudo-class applies while an element is
    being activated by the user. For example, between the times the user
    presses the mouse button and releases it. On systems with more than one
    mouse button, <code>:active</code> applies only to the primary or primary
    activation button (typically the "left" mouse button), and any aliases
    thereof.

   <li>The <code>:focus</code> pseudo-class applies while an element has the
    focus (accepts keyboard or mouse events, or other forms of input).
  </ul>

  <p>There may be document language or implementation specific limits on
   which elements can become <code>:active</code> or acquire
   <code>:focus</code>.

  <p>These pseudo-classes are not mutually exclusive. An element may match
   several pseudo-classes at the same time.

  <p>Selectors doesn't define if the parent of an element that is
   &lsquo;<code class=css>:active</code>&rsquo; or &lsquo;<code
   class=css>:hover</code>&rsquo; is also in that state.

  <p class=note><strong>Note:</strong> If the &lsquo;<code
   class=css>:hover</code>&rsquo; state applies to an element because its
   child is designated by a pointing device, then it's possible for
   &lsquo;<code class=css>:hover</code>&rsquo; to apply to an element that is
   not underneath the pointing device.

  <div class=example>
   <p>Examples:</p>

   <pre>a:link    /* unvisited links */
a:visited /* visited links */
a:hover   /* user hovers */
a:active  /* active links */</pre>

   <p>An example of combining dynamic pseudo-classes:</p>

   <pre>a:focus
a:focus:hover</pre>

   <p>The last selector matches <code>a</code> elements that are in the
    pseudo-class :focus and in the pseudo-class :hover.</p>
  </div>

  <p class=note><strong>Note:</strong> An element can be both &lsquo;<code
   class=css>:visited</code>&rsquo; and &lsquo;<code
   class=css>:active</code>&rsquo; (or &lsquo;<code
   class=css>:link</code>&rsquo; and &lsquo;<code
   class=css>:active</code>&rsquo;).

  <h4 id=target-pseudo><span class=secno>6.6.2. </span>The target
   pseudo-class :target</h4>

  <p>Some URIs refer to a location within a resource. This kind of URI ends
   with a &quot;number sign&quot; (#) followed by an anchor identifier
   (called the fragment identifier).

  <p>URIs with fragment identifiers link to a certain element within the
   document, known as the target element. For instance, here is a URI
   pointing to an anchor named <code>section_2</code> in an HTML document:

  <pre>http://example.com/html/top.html#section_2</pre>

  <p>A target element can be represented by the <code>:target</code>
   pseudo-class. If the document's URI has no fragment identifier, then the
   document has no target element.

  <div class=example>
   <p>Example:</p>

   <pre>p.note:target</pre>

   <p>This selector represents a <code>p</code> element of class
    <code>note</code> that is the target element of the referring URI.</p>
  </div>

  <div class=example>
   <p>CSS example:</p>

   <p>Here, the <code>:target</code> pseudo-class is used to make the target
    element red and place an image before it, if there is one:</p>

   <pre>*:target { color : red }
*:target::before { content : url(target.png) }</pre>
  </div>

  <h4 id=lang-pseudo><span class=secno>6.6.3. </span>The language
   pseudo-class :lang</h4>

  <p>If the document language specifies how the human language of an element
   is determined, it is possible to write selectors that represent an element
   based on its language. For example, in HTML <a href="#HTML401"
   rel=biblioentry>[HTML401]<!--{{HTML401}}--></a>, the language is
   determined by a combination of the <code>lang</code> attribute and
   possibly information from the <code>meta</code> elements or the protocol
   (such as HTTP headers). XML uses an attribute called
   <code>xml:lang</code>, and there may be other document language-specific
   methods for determining the language.

  <p>The pseudo-class <code>:lang(C)</code> represents an element that is in
   language C. Whether an element is represented by a <code>:lang()</code>
   selector is based solely on the element's language value (normalized to
   BCP 47 syntax if necessary) being equal to the identifier C, or beginning
   with the identifier C immediately followed by "-" (U+002D). The matching
   of C against the element's language value is performed case-insensitively.
   The identifier C does not have to be a valid language name.

  <p>C must be a valid CSS <a
   href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifier</a>
   <a href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a> and must not
   be empty. (Otherwise, the selector is invalid.)

  <p class=note><strong>Note:</strong> It is recommended that documents and
   protocols indicate language using codes from BCP 47 <a href="#BCP47"
   rel=biblioentry>[BCP47]<!--{{BCP47}}--></a> or its successor, and by means
   of "xml:lang" attributes in the case of XML-based documents <a
   href="#XML10" rel=biblioentry>[XML10]<!--{{XML10}}--></a>. See <a
   href="http://www.w3.org/International/questions/qa-lang-2or3.html"> "FAQ:
   Two-letter or three-letter language codes."</a>

  <div class=example>
   <p>Examples:</p>

   <p>The two following selectors represent an HTML document that is in
    Belgian French or German. The two next selectors represent <code>q</code>
    quotations in an arbitrary element in Belgian French or German.</p>

   <pre>html:lang(fr-be)
html:lang(de)
:lang(fr-be) &gt; q
:lang(de) &gt; q</pre>
  </div>

  <p>The difference between <code>:lang(C)</code> and the &lsquo;<code
   class=css>|=</code>&rsquo; operator is that the &lsquo;<code
   class=css>|=</code>&rsquo; operator only performs a comparison against a
   given attribute on the element, while the <code>:lang(C)</code>
   pseudo-class uses the UAs knowledge of the document's semantics to perform
   the comparison.

  <div class=example>
   <p>In this HTML example, only the BODY matches <code>[lang|=fr]</code>
    (because it has a LANG attribute) but both the BODY and the P match
    <code>:lang(fr)</code> (because both are in French). The P does not match
    the <code>[lang|=fr]</code> because it does not have a LANG attribute.</p>

   <pre>&lt;body lang=fr>
  &lt;p>Je suis fran&ccedil;ais.&lt;/p>
&lt;/body></pre>
  </div>

  <h4 id=UIstates><span class=secno>6.6.4. </span>The UI element states
   pseudo-classes</h4>

  <h5 id=enableddisabled><span class=secno>6.6.4.1. </span>The :enabled and
   :disabled pseudo-classes</h5>

  <p>The <code>:enabled</code> pseudo-class represents user interface
   elements that are in an enabled state; such elements have a corresponding
   disabled state.

  <p>Conversely, the <code>:disabled</code> pseudo-class represents user
   interface elements that are in a disabled state; such elements have a
   corresponding enabled state.

  <p>What constitutes an enabled state, a disabled state, and a user
   interface element is language-dependent. In a typical document most
   elements will be neither <code>:enabled</code> nor <code>:disabled</code>.

  <p class=note><strong>Note:</strong> CSS properties that might affect a
   user’s ability to interact with a given user interface element do not
   affect whether it matches <code>:enabled</code> or <code>:disabled</code>;
   e.g., the <code>display</code> and <code>visibility</code> properties have
   no effect on the enabled/disabled state of an element.

  <h5 id=checked><span class=secno>6.6.4.2. </span>The :checked pseudo-class</h5>

  <p>Radio and checkbox elements can be toggled by the user. Some menu items
   are "checked" when the user selects them. When such elements are toggled
   "on" the <code>:checked</code> pseudo-class applies. While the
   <code>:checked</code> pseudo-class is dynamic in nature, and can altered
   by user action, since it can also be based on the presence of semantic
   attributes in the document, it applies to all media. For example, the
   <code>:checked</code> pseudo-class initially applies to such elements that
   have the HTML4 <code>selected</code> and <code>checked</code> attributes
   as described in <a
   href="http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.2.1">Section
   17.2.1 of HTML4</a>, but of course the user can toggle "off" such elements
   in which case the <code>:checked</code> pseudo-class would no longer
   apply.

  <h5 id=indeterminate><span class=secno>6.6.4.3. </span>The :indeterminate
   pseudo-class</h5>

  <div class=note>
   <p><strong>Note:</strong> Radio and checkbox elements can be toggled by
    the user, but are sometimes in an indeterminate state, neither checked
    nor unchecked. This can be due to an element attribute, or DOM
    manipulation.</p>

   <p>A future version of this specification may introduce an
    <code>:indeterminate</code> pseudo-class that applies to such elements.
    <!--While the <code>:indeterminate</code> pseudo-class is dynamic in
nature, and is altered by user action, since it can also be based on
the presence of an element attribute, it applies to all media.</p>

<p>Components of a radio-group initialized with no pre-selected choice
are an example of :indeterminate state.--></p>
  </div>

  <h4 id=structural-pseudos><span class=secno>6.6.5. </span>Structural
   pseudo-classes</h4>

  <p>Selectors introduces the concept of <dfn
   id=structural-pseudo-classes>structural pseudo-classes</dfn> to permit
   selection based on extra information that lies in the document tree but
   cannot be represented by other simple selectors or combinators.

  <p>Standalone text and other non-element nodes are not counted when
   calculating the position of an element in the list of children of its
   parent. When calculating the position of an element in the list of
   children of its parent, the index numbering starts at 1.

  <h5 id=root-pseudo><span class=secno>6.6.5.1. </span>:root pseudo-class</h5>

  <p>The <code>:root</code> pseudo-class represents an element that is the
   root of the document. In HTML 4, this is always the <code>HTML</code>
   element.

  <h5 id=nth-child-pseudo><span class=secno>6.6.5.2. </span>:nth-child()
   pseudo-class</h5>

  <p>The <code>:nth-child(<var>a</var><code>n</code>+<var>b</var>)</code>
   pseudo-class notation represents an element that has
   <var>a</var><code>n</code>+<var>b</var>-1 siblings <strong>before</strong>
   it in the document tree, for any positive integer or zero value of
   <code>n</code>, and has a parent element. For values of <var>a</var> and
   <var>b</var> greater than zero, this effectively divides the element's
   children into groups of <var>a</var> elements (the last group taking the
   remainder), and selecting the <var>b</var>th element of each group. For
   example, this allows the selectors to address every other row in a table,
   and could be used to alternate the color of paragraph text in a cycle of
   four. The <var>a</var> and <var>b</var> values must be integers (positive,
   negative, or zero). The index of the first child of an element is 1.

  <p>In addition to this, <code>:nth-child()</code> can take &lsquo;<code
   class=css><code>odd</code></code>&rsquo; and &lsquo;<code
   class=css><code>even</code></code>&rsquo; as arguments instead.
   &lsquo;<code class=css><code>odd</code></code>&rsquo; has the same
   signification as <code>2n+1</code>, and &lsquo;<code
   class=css><code>even</code></code>&rsquo; has the same signification as
   <code>2n</code>.

  <p>The argument to <code>:nth-child()</code> must match the grammar below,
   where <code>INTEGER</code> matches the token <code>[0-9]+</code> and the
   rest of the tokenization is given by the <a href="#lex">Lexical
   scanner</a> in section 10.2:

  <pre>nth
  : S* [ ['-'|'+']? INTEGER? {N} [ S* ['-'|'+'] S* INTEGER ]? |
         ['-'|'+']? INTEGER | {O}{D}{D} | {E}{V}{E}{N} ] S*
  ;</pre>

  <div class=example>
   <p>Examples:</p>

   <pre>tr:nth-child(2n+1) /* represents every odd row of an HTML table */
tr:nth-child(odd)  /* same */
tr:nth-child(2n+0) /* represents every even row of an HTML table */
tr:nth-child(even) /* same */

/* Alternate paragraph colours in CSS */
p:nth-child(4n+1) { color: navy; }
p:nth-child(4n+2) { color: green; }
p:nth-child(4n+3) { color: maroon; }
p:nth-child(4n+4) { color: purple; }</pre>
  </div>

  <p>When the value <var>b</var> is preceded by a negative sign, the "+"
   character in the expression must be removed (it is effectively replaced by
   the "-" character indicating the negative value of <var>b</var>).

  <div class=example>
   <p>Examples:</p>

   <pre>:nth-child(10n-1)  /* represents the 9th, 19th, 29th, etc, element */
:nth-child(10n+9)  /* Same */
:nth-child(10n+-1) /* Syntactically invalid, and would be ignored */</pre>
  </div>

  <p>When <var>a</var>=0, the <var>a</var><code>n</code> part need not be
   included (unless the <var>b</var> part is already omitted). When
   <var>a</var><code>n</code> is not included and <var>b</var> is
   non-negative, the <code>+</code> sign before <var>b</var> (when allowed)
   may also be omitted. In this case the syntax simplifies to
   <code>:nth-child(<var>b</var>)</code>.

  <div class=example>
   <p>Examples:</p>

   <pre>foo:nth-child(0n+5)   /* represents an element foo that is the 5th child
                         of its parent element */
foo:nth-child(5)      /* same */</pre>
  </div>

  <p>When <var>a</var>=1, or <var>a</var>=-1, the number may be omitted from
   the rule.

  <div class=example>
   <p>Examples:</p>

   <p>The following selectors are therefore equivalent:</p>

   <pre>bar:nth-child(1n+0)   /* represents all bar elements, specificity (0,1,1) */
bar:nth-child(n+0)    /* same */
bar:nth-child(n)      /* same */
bar                   /* same but lower specificity (0,0,1) */</pre>
  </div>

  <p>If <var>b</var>=0, then every <var>a</var>th element is picked. In such
   a case, the +<var>b</var> (or -<var>b</var>) part may be omitted unless
   the <var>a</var> part is already omitted.

  <div class=example>
   <p>Examples:</p>

   <pre>tr:nth-child(2n+0) /* represents every even row of an HTML table */
tr:nth-child(2n) /* same */</pre>
  </div>

  <p>Whitespace is permitted after the "(", before the ")", and on either
   side of the "+" or "-" that separates the <var>a</var><code>n</code> and
   <var>b</var> parts when both are present.

  <div class=example>
   <p>Valid Examples with white space:</p>

   <pre>
:nth-child( 3n + 1 )
:nth-child( +3n - 2 )
:nth-child( -n+ 6)
:nth-child( +6 )
</pre>

   <p>Invalid Examples with white space:</p>

   <pre>
:nth-child(3 n)
:nth-child(+ 2n)
:nth-child(+ 2)
</pre>
  </div>

  <p>If both <var>a</var> and <var>b</var> are equal to zero, the
   pseudo-class represents no element in the document tree.

  <p>The value <var>a</var> can be negative, but only the positive values of
   <var>a</var><code>n</code>+<var>b</var>, for <code>n</code>&ge;0, may
   represent an element in the document tree.

  <div class=example>
   <p>Example:</p>

   <pre>html|tr:nth-child(-n+6)  /* represents the 6 first rows of XHTML tables */</pre>
  </div>

  <h5 id=nth-last-child-pseudo><span class=secno>6.6.5.3.
   </span>:nth-last-child() pseudo-class</h5>

  <p>The <code>:nth-last-child(<var>a</var>n+<var>b</var>)</code>
   pseudo-class notation represents an element that has
   <var>a</var><code>n</code>+<var>b</var>-1 siblings <strong>after</strong>
   it in the document tree, for any positive integer or zero value of
   <code>n</code>, and has a parent element. See <a
   href="#nth-child-pseudo"><code>:nth-child()</code></a> pseudo-class for
   the syntax of its argument. It also accepts the &lsquo;<code
   class=css><code>even</code></code>&rsquo; and &lsquo;<code
   class=css><code>odd</code></code>&rsquo; values as arguments.

  <div class=example>
   <p>Examples:</p>

   <pre>tr:nth-last-child(-n+2)    /* represents the two last rows of an HTML table */

foo:nth-last-child(odd)    /* represents all odd foo elements in their parent element,
                              counting from the last one */</pre>
  </div>

  <h5 id=nth-of-type-pseudo><span class=secno>6.6.5.4. </span>:nth-of-type()
   pseudo-class</h5>

  <p>The <code>:nth-of-type(<var>a</var>n+<var>b</var>)</code> pseudo-class
   notation represents an element that has
   <var>a</var><code>n</code>+<var>b</var>-1 siblings with the same expanded
   element name <strong>before</strong> it in the document tree, for any zero
   or positive integer value of <code>n</code>, and has a parent element. See
   <a href="#nth-child-pseudo"><code>:nth-child()</code></a> pseudo-class for
   the syntax of its argument. It also accepts the &lsquo;<code
   class=css><code>even</code></code>&rsquo; and &lsquo;<code
   class=css><code>odd</code></code>&rsquo; values.

  <div class=example>
   <p>CSS example:</p>

   <p>This allows an author to alternate the position of floated images:</p>

   <pre>img:nth-of-type(2n+1) { float: right; }
img:nth-of-type(2n) { float: left; }</pre>
  </div>

  <h5 id=nth-last-of-type-pseudo><span class=secno>6.6.5.5.
   </span>:nth-last-of-type() pseudo-class</h5>

  <p>The <code>:nth-last-of-type(<var>a</var>n+<var>b</var>)</code>
   pseudo-class notation represents an element that has
   <var>a</var><code>n</code>+<var>b</var>-1 siblings with the same expanded
   element name <strong>after</strong> it in the document tree, for any zero
   or positive integer value of <code>n</code>, and has a parent element. See
   <a href="#nth-child-pseudo"><code>:nth-child()</code></a> pseudo-class for
   the syntax of its argument. It also accepts the &lsquo;<code
   class=css><code>even</code></code>&rsquo; and &lsquo;<code
   class=css><code>odd</code></code>&rsquo; values.

  <div class=example>
   <p>Example:</p>

   <p>To represent all <code>h2</code> children of an XHTML <code>body</code>
    except the first and last, one could use the following selector:</p>

   <pre>body &gt; h2:nth-of-type(n+2):nth-last-of-type(n+2)</pre>

   <p>In this case, one could also use <code>:not()</code>, although the
    selector ends up being just as long:</p>

   <pre>body &gt; h2:not(:first-of-type):not(:last-of-type)</pre>
  </div>

  <h5 id=first-child-pseudo><span class=secno>6.6.5.6. </span>:first-child
   pseudo-class</h5>

  <p>Same as <code>:nth-child(1)</code>. The <code>:first-child</code>
   pseudo-class represents an element that is the first child of some other
   element.

  <div class=example>
   <p>Examples:</p>

   <p>The following selector represents a <code>p</code> element that is the
    first child of a <code>div</code> element:</p>

   <pre>div &gt; p:first-child</pre>

   <p>This selector can represent the <code>p</code> inside the
    <code>div</code> of the following fragment:</p>

   <pre>&lt;p&gt; The last P before the note.&lt;/p&gt;
&lt;div class="note"&gt;
   &lt;p&gt; The first P inside the note.&lt;/p&gt;
&lt;/div&gt;</pre>
   but cannot represent the second <code>p</code> in the following fragment:
   <pre>&lt;p&gt; The last P before the note.&lt;/p&gt;
&lt;div class="note"&gt;
   &lt;h2&gt; Note &lt;/h2&gt;
   &lt;p&gt; The first P inside the note.&lt;/p&gt;
&lt;/div&gt;</pre>

   <p>The following two selectors are usually equivalent:</p>

   <pre>* &gt; a:first-child /* a is first child of any element */
a:first-child /* Same (assuming a is not the root element) */</pre>
  </div>

  <h5 id=last-child-pseudo><span class=secno>6.6.5.7. </span>:last-child
   pseudo-class</h5>

  <p>Same as <code>:nth-last-child(1)</code>. The <code>:last-child</code>
   pseudo-class represents an element that is the last child of some other
   element.

  <div class=example>
   <p>Example:</p>

   <p>The following selector represents a list item <code>li</code> that is
    the last child of an ordered list <code>ol</code>.

   <pre>ol &gt; li:last-child</pre>
  </div>

  <h5 id=first-of-type-pseudo><span class=secno>6.6.5.8.
   </span>:first-of-type pseudo-class</h5>

  <p>Same as <code>:nth-of-type(1)</code>. The <code>:first-of-type</code>
   pseudo-class represents an element that is the first sibling of its type
   in the list of children of its parent element.

  <div class=example>
   <p>Example:</p>

   <p>The following selector represents a definition title <code>dt</code>
    inside a definition list <code>dl</code>, this <code>dt</code> being the
    first of its type in the list of children of its parent element.</p>

   <pre>dl dt:first-of-type</pre>

   <p>It is a valid description for the first two <code>dt</code> elements in
    the following example but not for the third one:</p>

   <pre>&lt;dl&gt;
 &lt;dt&gt;gigogne&lt;/dt&gt;
 &lt;dd&gt;
  &lt;dl&gt;
   &lt;dt&gt;fus&eacute;e&lt;/dt&gt;
   &lt;dd&gt;multistage rocket&lt;/dd&gt;
   &lt;dt&gt;table&lt;/dt&gt;
   &lt;dd&gt;nest of tables&lt;/dd&gt;
  &lt;/dl&gt;
 &lt;/dd&gt;
&lt;/dl&gt;</pre>
  </div>

  <h5 id=last-of-type-pseudo><span class=secno>6.6.5.9. </span>:last-of-type
   pseudo-class</h5>

  <p>Same as <code>:nth-last-of-type(1)</code>. The
   <code>:last-of-type</code> pseudo-class represents an element that is the
   last sibling of its type in the list of children of its parent element.

  <div class=example>
   <p>Example:</p>

   <p>The following selector represents the last data cell <code>td</code> of
    a table row <code>tr</code>.</p>

   <pre>tr &gt; td:last-of-type</pre>
  </div>

  <h5 id=only-child-pseudo><span class=secno>6.6.5.10. </span>:only-child
   pseudo-class</h5>

  <p>Represents an element that has a parent element and whose parent element
   has no other element children. Same as
   <code>:first-child:last-child</code> or
   <code>:nth-child(1):nth-last-child(1)</code>, but with a lower
   specificity.

  <h5 id=only-of-type-pseudo><span class=secno>6.6.5.11. </span>:only-of-type
   pseudo-class</h5>

  <p>Represents an element that has a parent element and whose parent element
   has no other element children with the same expanded element name. Same as
   <code>:first-of-type:last-of-type</code> or
   <code>:nth-of-type(1):nth-last-of-type(1)</code>, but with a lower
   specificity.

  <h5 id=empty-pseudo><span class=secno>6.6.5.12. </span>:empty pseudo-class</h5>

  <p>The <code>:empty</code> pseudo-class represents an element that has no
   children at all. In terms of the document tree, only element nodes and
   content nodes (such as DOM <a href="#DOM-LEVEL-3-CORE"
   rel=biblioentry>[DOM-LEVEL-3-CORE]<!--{{DOM-LEVEL-3-CORE}}--></a> text
   nodes, CDATA nodes, and entity references) whose data has a non-zero
   length must be considered as affecting emptiness; comments, processing
   instructions, and other nodes must not affect whether an element is
   considered empty or not.

  <div class=example>
   <p>Examples:</p>

   <p><code>p:empty</code> is a valid representation of the following
    fragment:</p>

   <pre>&lt;p&gt;&lt;/p&gt;</pre>

   <p><code>foo:empty</code> is not a valid representation for the following
    fragments:</p>

   <pre>&lt;foo&gt;bar&lt;/foo&gt;</pre>

   <pre>&lt;foo&gt;&lt;bar&gt;bla&lt;/bar&gt;&lt;/foo&gt;</pre>

   <pre>&lt;foo&gt;this is not &lt;bar&gt;:empty&lt;/bar&gt;&lt;/foo&gt;</pre>
  </div>

  <h4 id=content-selectors><span class=secno>6.6.6. </span>Blank</h4>
  <!-- It's the Return of Appendix H!!! Run away! -->

  <p>This section intentionally left blank. (This section previously defined
   a <code>:contains()</code> pseudo-class.)</p>
  <!-- (used to be :contains()) -->

  <h4 id=negation><span class=secno>6.6.7. </span>The negation pseudo-class</h4>

  <p>The negation pseudo-class, <code>:not(<var>X</var>)</code>, is a
   functional notation taking a <a href="#simple-selectors-dfn">simple
   selector</a> (excluding the negation pseudo-class itself) as an argument.
   It represents an element that is not represented by its argument.

  <p>Negations may not be nested; <code>:not(:not(...))</code> is invalid.
   Note also that since pseudo-elements are not simple selectors, they are
   not a valid argument to <code>:not()</code>.

  <div class=example>
   <p>Examples:</p>

   <p>The following selector matches all <code>button</code> elements in an
    HTML document that are not disabled.</p>

   <pre>button:not([DISABLED])</pre>

   <p>The following selector represents all but <code>FOO</code> elements.</p>

   <pre>*:not(FOO)</pre>

   <p>The following group of selectors represents all HTML elements except
    links.</p>

   <pre>html|*:not(:link):not(:visited)</pre>
  </div>

  <p>Default namespace declarations do not affect the argument of the
   negation pseudo-class unless the argument is a universal selector or a
   type selector.

  <div class=example>
   <p>Examples:</p>

   <p>Assuming that the default namespace is bound to "http://example.com/",
    the following selector represents all elements that are not in that
    namespace:</p>

   <pre>*|*:not(*)</pre>

   <p>The following selector matches any element that is not being hovered,
    regardless of its namespace. In particular, it is not limited to only
    matching elements in the default namespace that are not being hovered,
    and elements not in the default namespace don't match the rule when they
    <em>are</em> being hovered.</p>

   <pre>*|*:not(:hover)</pre>
  </div>

  <p class=note><strong>Note</strong>: the :not() pseudo allows useless
   selectors to be written. For instance <code>:not(*|*)</code>, which
   represents no element at all, or <code>foo:not(bar)</code>, which is
   equivalent to <code>foo</code> but with a higher specificity.

  <h2 id=pseudo-elements><span class=secno>7. </span>Pseudo-elements</h2>

  <p>Pseudo-elements create abstractions about the document tree beyond those
   specified by the document language. For instance, document languages do
   not offer mechanisms to access the first letter or first line of an
   element's content. Pseudo-elements allow authors to refer to this
   otherwise inaccessible information. Pseudo-elements may also provide
   authors a way to refer to content that does not exist in the source
   document (e.g., the <code>::before</code> and <code>::after</code>
   pseudo-elements give access to generated content).

  <p>A pseudo-element is made of two colons (<code>::</code>) followed by the
   name of the pseudo-element.

  <p>This <code>::</code> notation is introduced by the current document in
   order to establish a discrimination between pseudo-classes and
   pseudo-elements. For compatibility with existing style sheets, user agents
   must also accept the previous one-colon notation for pseudo-elements
   introduced in CSS levels 1 and 2 (namely, <code>:first-line</code>,
   <code>:first-letter</code>, <code>:before</code> and <code>:after</code>).
   This compatibility is not allowed for the new pseudo-elements introduced
   in this specification.

  <p>Only one pseudo-element may appear per selector, and if present it must
   appear after the sequence of simple selectors that represents the <a
   href="#subject">subjects</a> of the selector. <span
   class=note><strong>Note:</strong> A future version of this specification
   may allow multiple pseudo-elements per selector.</span>

  <h3 id=first-line><span class=secno>7.1. </span>The ::first-line
   pseudo-element</h3>

  <p>The <code>::first-line</code> pseudo-element describes the contents of
   the first formatted line of an element.

  <div class=example>
   <p>CSS example:</p>

   <pre>p::first-line { text-transform: uppercase }</pre>

   <p>The above rule means "change the letters of the first line of every
    <code>p</code> element to uppercase".</p>

   <p>The selector <code>p::first-line</code> does not match any real
    document element. It does match a pseudo-element that conforming user
    agents will insert at the beginning of every <code>p</code> element.</p>
  </div>

  <p>Note that the length of the first line depends on a number of factors,
   including the width of the page, the font size, etc. Thus, an ordinary
   HTML paragraph such as:

  <pre>
&lt;P&gt;This is a somewhat long HTML 
paragraph that will be broken into several 
lines. The first line will be identified
by a fictional tag sequence. The other lines 
will be treated as ordinary lines in the 
paragraph.&lt;/P&gt;
</pre>

  <p>the lines of which happen to be broken as follows:

  <pre>
THIS IS A SOMEWHAT LONG HTML PARAGRAPH THAT
will be broken into several lines. The first
line will be identified by a fictional tag 
sequence. The other lines will be treated as 
ordinary lines in the paragraph.
</pre>

  <p>This paragraph might be "rewritten" by user agents to include the
   <em>fictional tag sequence</em> for <code>::first-line</code>. This
   fictional tag sequence helps to show how properties are inherited.

  <pre>
&lt;P&gt;<b>&lt;P::first-line&gt;</b> This is a somewhat long HTML 
paragraph that <b>&lt;/P::first-line&gt;</b> will be broken into several
lines. The first line will be identified 
by a fictional tag sequence. The other lines 
will be treated as ordinary lines in the 
paragraph.&lt;/P&gt;
</pre>

  <p>If a pseudo-element breaks up a real element, the desired effect can
   often be described by a fictional tag sequence that closes and then
   re-opens the element. Thus, if we mark up the previous paragraph with a
   <code>span</code> element:

  <pre>
&lt;P&gt;<b>&lt;SPAN class="test"&gt;</b> This is a somewhat long HTML
paragraph that will be broken into several
lines.<b>&lt;/SPAN&gt;</b> The first line will be identified
by a fictional tag sequence. The other lines 
will be treated as ordinary lines in the 
paragraph.&lt;/P&gt;
</pre>

  <p>the user agent could simulate start and end tags for <code>span</code>
   when inserting the fictional tag sequence for <code>::first-line</code>.

  <pre>
&lt;P&gt;&lt;P::first-line&gt;<b>&lt;SPAN class="test"&gt;</b> This is a
somewhat long HTML
paragraph that will <b>&lt;/SPAN&gt;</b>&lt;/P::first-line&gt;<b>&lt;SPAN class="test"&gt;</b> be
broken into several
lines.<b>&lt;/SPAN&gt;</b> The first line will be identified
by a fictional tag sequence. The other lines
will be treated as ordinary lines in the 
paragraph.&lt;/P&gt;
</pre>

  <h4 id=first-formatted-line><span class=secno>7.1.1. </span><dfn
   id=first-formatted-line0>First formatted line</dfn> definition in CSS</h4>

  <p>In CSS, the <code>::first-line</code> pseudo-element can only have an
   effect when attached to a block-like container such as a block box,
   inline-block, table-caption, or table-cell.

  <p>The first formatted line of an element may occur inside a block-level
   descendant in the same flow (i.e., a block-level descendant that is not
   out-of-flow due to floating or positioning). For example, the first line
   of the <code>DIV</code> in <code>&lt;DIV>&lt;P>This
   line...&lt;/P>&lt/DIV></code> is the first line of the <code>P</code>
   (assuming that both <code>P</code> and <code>DIV</code> are block-level).

  <p>The first line of a table-cell or inline-block cannot be the first
   formatted line of an ancestor element. Thus, in <code>&lt;DIV&gt;&lt;P
   STYLE="display: inline-block">Hello&lt;BR&gt;Goodbye&lt;/P&gt;
   etcetera&lt;/DIV&gt;</code> the first formatted line of the <code>DIV
   </code> is not the line "Hello".

  <p class=note><strong>Note:</strong> Note that the first line of the
   <code>p</code> in this fragment: <code>&lt;p&gt&lt;br&gt;First...</code>
   doesn't contain any letters (assuming the default style for
   <code>br</code> in HTML 4). The word "First" is not on the first formatted
   line.

  <p>A UA should act as if the fictional start tags of the
   <code>::first-line</code> pseudo-elements were nested just inside the
   innermost enclosing block-level element. (Since CSS1 and CSS2 were silent
   on this case, authors should not rely on this behavior.) For example, the
   fictional tag sequence for

  <pre>
&lt;DIV>
  &lt;P>First paragraph&lt;/P>
  &lt;P>Second paragraph&lt;/P>
&lt;/DIV>
</pre>

  <p>is

  <pre>
&lt;DIV>
  &lt;P>&lt;DIV::first-line>&lt;P::first-line>First paragraph&lt;/P::first-line>&lt;/DIV::first-line>&lt;/P>
  &lt;P>&lt;P::first-line>Second paragraph&lt;/P::first-line>&lt;/P>
&lt;/DIV>
</pre>

  <p>The <code>::first-line</code> pseudo-element is similar to an
   inline-level element, but with certain restrictions. The following CSS
   properties apply to a <code>::first-line</code> pseudo-element: font
   properties, color property, background properties, &lsquo;<code
   class=property>word-spacing</code>&rsquo;, &lsquo;<code
   class=property>letter-spacing</code>&rsquo;, &lsquo;<code
   class=property>text-decoration</code>&rsquo;, &lsquo;<code
   class=property>vertical-align</code>&rsquo;, &lsquo;<code
   class=property>text-transform</code>&rsquo;, &lsquo;<code
   class=property>line-height</code>&rsquo;. UAs may apply other properties
   as well.

  <p>During CSS inheritance, the portion of a child element that occurs on
   the first line only inherits properties applicable to the
   <code>::first-line</code> pseudo-element from the
   <code>::first-line</code> pseudo-element. For all other properties
   inheritence is from the non-pseudo-element parent of the first line pseudo
   element. (The portion of a child element that does not occur on the first
   line always inherits from the parent of that child.)

  <h3 id=first-letter><span class=secno>7.2. </span>The ::first-letter
   pseudo-element</h3>

  <p>The <code>::first-letter</code> pseudo-element represents the first
   letter of an element, if it is not preceded by any other content (such as
   images or inline tables) on its line. The ::first-letter pseudo-element
   may be used for "initial caps" and "drop caps", which are common
   typographical effects.

  <p>Punctuation (i.e, characters defined in Unicode in the "open" (Ps),
   "close" (Pe), "initial" (Pi). "final" (Pf) and "other" (Po) punctuation
   classes), that precedes or follows the first letter should be included. <a
   href="#UNICODE" rel=biblioentry>[UNICODE]<!--{{!UNICODE}}--></a>

  <div class=figure>
   <p><img alt="Quotes that precede the first letter should be included."
    src=first-letter2.png></p>
  </div>

  <p>The <code>::first-letter</code> also applies if the first letter is in
   fact a digit, e.g., the "6" in "67 million dollars is a lot of money."

  <p class=note><strong>Note:</strong> In some cases the
   <code>::first-letter</code> pseudo-element should include more than just
   the first non-punctuation character on a line. For example, combining
   characters must be kept with their base character. Additionally, some
   languages may have specific rules about how to treat certain letter
   combinations. The UA definition of <code>::first-letter</code> should
   include at least the default grapheme cluster as defined by UAX29 and may
   include more than that as appropriate. In Dutch, for example, if the
   letter combination "ij" appears at the beginning of an element, both
   letters should be considered within the <code>::first-letter</code>
   pseudo-element. <a href="#UAX29"
   rel=biblioentry>[UAX29]<!--{{UAX29}}--></a>

  <p>If the letters that would form the <code>::first-letter</code> are not
   in the same element, such as "&lsquo;<code class=css>T" in
   <code>&lt;p>'&lt;em>T...</code>, the UA may create a
   <code>::first-letter</code> pseudo-element from one of the elements, both
   elements, or simply not create a pseudo-element.</code>

  <p>Similarly, if the first letter(s) of the block are not at the start of
   the line (for example due to bidirectional reordering), then the UA need
   not create the pseudo-element(s).

  <div class=example>
   <p>Example:</p>

   <p><a name=overlapping-example>The following CSS and HTML example</a>
    illustrates how overlapping pseudo-elements may interact. The first
    letter of each P element will be green with a font size of &rsquo;24pt'.
    The rest of the first formatted line will be &lsquo;<code
    class=property>blue</code>&rsquo; while the rest of the paragraph will be
    &lsquo;<code class=property>red</code>&rsquo;.</p>

   <pre>p { color: red; font-size: 12pt }
p::first-letter { color: green; font-size: 200% }
p::first-line { color: blue }

&lt;P&gt;Some text that ends up on two lines&lt;/P&gt;</pre>

   <p>Assuming that a line break will occur before the word "ends", the <span
    class=index-inst id=fictional-tag-sequence title="fictional tag
    sequence">fictional tag sequence</span> for this fragment might be:</p>

   <pre>&lt;P&gt;
&lt;P::first-line&gt;
&lt;P::first-letter&gt; 
S 
&lt;/P::first-letter&gt;ome text that 
&lt;/P::first-line&gt; 
ends up on two lines 
&lt;/P&gt;</pre>

   <p>Note that the <code>::first-letter</code> element is inside the
    <code>::first-line</code> element. Properties set on
    <code>::first-line</code> are inherited by <code>::first-letter</code>,
    but are overridden if the same property is set on
    <code>::first-letter</code>.</p>
  </div>

  <p>The first letter must occur on the <a href="#first-formatted-line">first
   formatted line.</a> For example, in this HTML fragment:
   <code>&lt;p&gt&lt;br&gt;First...</code> the first line doesn't contain any
   letters and <code>::first-letter</code> doesn't match anything (assuming
   the default style for <code>br</code> in HTML 4). In particular, it does
   not match the "F" of "First."

  <h4 id=application-in-css><span class=secno>7.2.1. </span>Application in
   CSS</h4>

  <p>In CSS, the <code>::first-letter</code> pseudo-element applies to
   block-like containers such as block, list-item, table-cell, table-caption,
   and inline-block elements. <span class=note><strong>Note:</strong> A
   future version of this specification may allow this pseudo-element to
   apply to more display types.</span>

  <p>The <code>::first-letter</code> pseudo-element can be used with all such
   elements that contain text, or that have a descendant in the same flow
   that contains text. A UA should act as if the fictional start tag of the
   ::first-letter pseudo-element is just before the first text of the
   element, even if that first text is in a descendant.

  <div class=example>
   <p>Example:</p>

   <p>The fictional tag sequence for this HTML fragment:

   <pre>&lt;div>
&lt;p>The first text.</pre>

   <p>is:

   <pre>&lt;div>
&lt;p>&lt;div::first-letter>&lt;p::first-letter>T&lt;/...>&lt;/...>he first text.</pre>
  </div>

  <p>In CSS the first letter of a table-cell or inline-block cannot be the
   first letter of an ancestor element. Thus, in <code>&lt;DIV&gt;&lt;P
   STYLE="display: inline-block">Hello&lt;BR&gt;Goodbye&lt;/P&gt;
   etcetera&lt;/DIV&gt;</code> the first letter of the <code>DIV</code> is
   not the letter "H". In fact, the <code>DIV</code> doesn't have a first
   letter.

  <p>If an element is a list item (&lsquo;<code class=css>display:
   list-item</code>&rsquo;), the <code>::first-letter</code> applies to the
   first letter in the principal box after the marker. UAs may ignore
   <code>::first-letter</code> on list items with &lsquo;<code
   class=css>list-style-position: inside</code>&rsquo;. If an element has
   <code>::before</code> or <code>::after</code> content, the
   <code>::first-letter</code> applies to the first letter of the element
   <em>including</em> that content.

  <div class=example>
   <p>Example:</p>

   <p>After the rule <code>p::before {content: "Note: "}</code>, the selector
    <code>p::first-letter</code> matches the "N" of "Note".</p>
  </div>

  <p>In CSS a ::first-line pseudo-element is similar to an inline-level
   element if its &lsquo;<code class=property>float</code>&rsquo; property is
   &lsquo;<code class=property>none</code>&rsquo;; otherwise, it is similar
   to a floated element. The following properties that apply to
   <code>::first-letter</code> pseudo-elements: font properties, &lsquo;<code
   class=property>text-decoration</code>&rsquo;, &lsquo;<code
   class=property>text-transform</code>&rsquo;, &lsquo;<code
   class=property>letter-spacing</code>&rsquo;, &lsquo;<code
   class=property>word-spacing</code>&rsquo; (when appropriate), &lsquo;<code
   class=property>line-height</code>&rsquo;, &lsquo;<code
   class=property>float</code>&rsquo;, &lsquo;<code
   class=property>vertical-align</code>&rsquo; (only if &lsquo;<code
   class=property>float</code>&rsquo; is &lsquo;<code
   class=property>none</code>&rsquo;), margin properties, padding properties,
   border properties, color property, background properties. UAs may apply
   other properties as well. To allow UAs to render a typographically correct
   drop cap or initial cap, the UA may choose a line-height, width and height
   based on the shape of the letter, unlike for normal elements.

  <div class=example>
   <p>Example:</p>

   <p>This CSS and HTML example shows a possible rendering of an initial cap.
    Note that the &lsquo;<code class=property>line-height</code>&rsquo; that
    is inherited by the <code>::first-letter</code> pseudo-element is 1.1,
    but the UA in this example has computed the height of the first letter
    differently, so that it doesn't cause any unnecessary space between the
    first two lines. Also note that the fictional start tag of the first
    letter is inside the <span>span</span>, and thus the font weight of the
    first letter is normal, not bold as the <span>span</span>:

   <pre>
p { line-height: 1.1 }
p::first-letter { font-size: 3em; font-weight: normal }
span { font-weight: bold }
...
&lt;p>&lt;span>Het hemelsche&lt;/span> gerecht heeft zich ten lange lesten&lt;br>
Erbarremt over my en mijn benaeuwde vesten&lt;br>
En arme burgery, en op mijn volcx gebed&lt;br>
En dagelix geschrey de bange stad ontzet.
</pre>

   <div class=figure>
    <p><img alt="Image illustrating the ::first-letter pseudo-element"
     src=initial-cap.png>
   </div>
  </div>

  <div class=example>
   <p>The following CSS will make a drop cap initial letter span about two
    lines:</p>

   <pre>
&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"&gt;
&lt;HTML&gt;
 &lt;HEAD&gt;
  &lt;TITLE&gt;Drop cap initial letter&lt;/TITLE&gt;
  &lt;STYLE type="text/css"&gt;
   P               { font-size: 12pt; line-height: 1.2 }
   P::first-letter { font-size: 200%; font-weight: bold; float: left }
   SPAN            { text-transform: uppercase }
  &lt;/STYLE&gt;
 &lt;/HEAD&gt;
 &lt;BODY&gt;
  &lt;P&gt;&lt;SPAN&gt;The first&lt;/SPAN&gt; few words of an article
    in The Economist.&lt;/P&gt;
 &lt;/BODY&gt;
&lt;/HTML&gt;
</pre>

   <p>This example might be formatted as follows:</p>

   <div class=figure>
    <p><img alt="Image illustrating the combined effect of the ::first-letter
     and ::first-line pseudo-elements" src=first-letter.png></p>
   </div>

   <p>The <span class=index-inst id=fictional-tag-sequence0 title="fictional
    tag sequence">fictional tag sequence</span> is:</p>

   <pre>
&lt;P&gt;
&lt;SPAN&gt;
&lt;P::first-letter&gt;
T
&lt;/P::first-letter&gt;he first
&lt;/SPAN&gt; 
few words of an article in the Economist.
&lt;/P&gt;
</pre>

   <p>Note that the <code>::first-letter</code> pseudo-element tags abut the
    content (i.e., the initial character), while the ::first-line
    pseudo-element start tag is inserted right after the start tag of the
    block element.</p>
  </div>

  <p>In order to achieve traditional drop caps formatting, user agents may
   approximate font sizes, for example to align baselines. Also, the glyph
   outline may be taken into account when formatting.

  <h3 id=selection><span class=secno>7.3. </span>Blank</h3>

  <p>This section intentionally left blank. (This section previously defined
   a <code>::selection</code> pseudo-element.)

  <h3 id=gen-content><span class=secno>7.4. </span>The ::before and ::after
   pseudo-elements</h3>

  <p>The <code>::before</code> and <code>::after</code> pseudo-elements can
   be used to describe generated content before or after an element's
   content. They are explained in CSS 2.1 <a href="#CSS21"
   rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>.

  <p>When the <code>::first-letter</code> and <code>::first-line</code>
   pseudo-elements are applied to an element having content generated using
   <code>::before</code> or <code>::after</code>, they apply to the first
   letter or line of the element including the generated content.

  <h2 id=combinators><span class=secno>8. </span>Combinators</h2>

  <h3 id=descendant-combinators><span class=secno>8.1. </span>Descendant
   combinator</h3>

  <p>At times, authors may want selectors to describe an element that is the
   descendant of another element in the document tree (e.g., "an
   <code>EM</code> element that is contained within an <code>H1</code>
   element"). Descendant combinators express such a relationship. A
   descendant combinator is <a href="#whitespace">whitespace</a> that
   separates two sequences of simple selectors. A selector of the form
   "<code>A B</code>" represents an element <code>B</code> that is an
   arbitrary descendant of some ancestor element <code>A</code>.

  <div class=example>
   <p>Examples:</p>

   <p>For example, consider the following selector:</p>

   <pre>h1 em</pre>

   <p>It represents an <code>em</code> element being the descendant of an
    <code>h1</code> element. It is a correct and valid, but partial,
    description of the following fragment:</p>

   <pre>&lt;h1&gt;This &lt;span class="myclass"&gt;headline
is &lt;em&gt;very&lt;/em&gt; important&lt;/span&gt;&lt;/h1&gt;</pre>

   <p>The following selector:</p>

   <pre>div * p</pre>

   <p>represents a <code>p</code> element that is a grandchild or later
    descendant of a <code>div</code> element. Note the whitespace on either
    side of the "*" is not part of the universal selector; the whitespace is
    a combinator indicating that the <code>div</code> must be the ancestor of
    some element, and that that element must be an ancestor of the
    <code>p</code>.</p>

   <p>The following selector, which combines descendant combinators and <a
    href="#attribute-selectors">attribute selectors</a>, represents an
    element that (1) has the <code>href</code> attribute set and (2) is
    inside a <code>p</code> that is itself inside a <code>div</code>:</p>

   <pre>div p *[href]</pre>
  </div>

  <h3 id=child-combinators><span class=secno>8.2. </span>Child combinators</h3>

  <p>A <dfn id=child-combinator>child combinator</dfn> describes a childhood
   relationship between two elements. A child combinator is made of the
   &quot;greater-than sign&quot; (U+003E, <code>&gt;</code>) character and
   separates two sequences of simple selectors.

  <div class=example>
   <p>Examples:</p>

   <p>The following selector represents a <code>p</code> element that is
    child of <code>body</code>:</p>

   <pre>body &gt; p</pre>

   <p>The following example combines descendant combinators and child
    combinators.</p>

   <pre>div ol&gt;li p</pre>
   <!-- LEAVE THOSE SPACES OUT! see below -->
   <p>It represents a <code>p</code> element that is a descendant of an
    <code>li</code> element; the <code>li</code> element must be the child of
    an <code>ol</code> element; the <code>ol</code> element must be a
    descendant of a <code>div</code>. Notice that the optional white space
    around the "&gt;" combinator has been left out.</p>
  </div>

  <p>For information on selecting the first child of an element, please see
   the section on the <code><a
   href="#structural-pseudos">:first-child</a></code> pseudo-class above.

  <h3 id=sibling-combinators><span class=secno>8.3. </span>Sibling
   combinators</h3>

  <p>There are two different sibling combinators: the adjacent sibling
   combinator and the general sibling combinator. In both cases, non-element
   nodes (e.g. text between elements) are ignored when considering adjacency
   of elements.

  <h4 id=adjacent-sibling-combinators><span class=secno>8.3.1.
   </span>Adjacent sibling combinator</h4>

  <p>The adjacent sibling combinator is made of the &quot;plus sign&quot;
   (U+002B, <code>+</code>) character that separates two sequences of simple
   selectors. The elements represented by the two sequences share the same
   parent in the document tree and the element represented by the first
   sequence immediately precedes the element represented by the second one.

  <div class=example>
   <p>Examples:</p>

   <p>The following selector represents a <code>p</code> element immediately
    following a <code>math</code> element:</p>

   <pre>math + p</pre>

   <p>The following selector is conceptually similar to the one in the
    previous example, except that it adds an attribute selector &mdash; it
    adds a constraint to the <code>h1</code> element, that it must have
    <code>class="opener"</code>:</p>

   <pre>h1.opener + h2</pre>
  </div>

  <h4 id=general-sibling-combinators><span class=secno>8.3.2. </span>General
   sibling combinator</h4>

  <p>The general sibling combinator is made of the &quot;tilde&quot; (U+007E,
   <code>~</code>) character that separates two sequences of simple
   selectors. The elements represented by the two sequences share the same
   parent in the document tree and the element represented by the first
   sequence precedes (not necessarily immediately) the element represented by
   the second one.

  <div class=example>
   <p>Example:</p>

   <pre>h1 ~ pre</pre>

   <p>represents a <code>pre</code> element following an <code>h1</code>. It
    is a correct and valid, but partial, description of:</p>

   <pre>&lt;h1&gt;Definition of the function a&lt;/h1&gt;
&lt;p&gt;Function a(x) has to be applied to all figures in the table.&lt;/p&gt;
&lt;pre&gt;function a(x) = 12x/13.5&lt;/pre&gt;</pre>
  </div>

  <h2 id=specificity><span class=secno>9. </span>Calculating a selector's
   specificity</h2>

  <p>A selector's specificity is calculated as follows:

  <ul>
   <li>count the number of ID selectors in the selector (= a)

   <li>count the number of class selectors, attributes selectors, and
    pseudo-classes in the selector (= b)

   <li>count the number of type selectors and pseudo-elements in the selector
    (= c)

   <li>ignore the universal selector
  </ul>

  <p>Selectors inside <a href="#negation">the negation pseudo-class</a> are
   counted like any other, but the negation itself does not count as a
   pseudo-class.

  <p>Concatenating the three numbers a-b-c (in a number system with a large
   base) gives the specificity.

  <div class=example>
   <p>Examples:</p>

   <pre>*               /* a=0 b=0 c=0 -&gt; specificity =   0 */
LI              /* a=0 b=0 c=1 -&gt; specificity =   1 */
UL LI           /* a=0 b=0 c=2 -&gt; specificity =   2 */
UL OL+LI        /* a=0 b=0 c=3 -&gt; specificity =   3 */
H1 + *[REL=up]  /* a=0 b=1 c=1 -&gt; specificity =  11 */
UL OL LI.red    /* a=0 b=1 c=3 -&gt; specificity =  13 */
LI.red.level    /* a=0 b=2 c=1 -&gt; specificity =  21 */
#x34y           /* a=1 b=0 c=0 -&gt; specificity = 100 */
#s12:not(FOO)   /* a=1 b=0 c=1 -&gt; specificity = 101 */
</pre>
  </div>

  <p class=note><strong>Note:</strong> Repeated occurrances of the same
   simple selector are allowed and do increase specificity.

  <p class=note><strong>Note:</strong> the specificity of the styles
   specified in an HTML <code>style</code> attribute is described in CSS 2.1.
   <a href="#CSS21" rel=biblioentry>[CSS21]<!--{{!CSS21}}--></a>.

  <h2 id=w3cselgrammar><span class=secno>10. </span>The grammar of Selectors</h2>

  <h3 id=grammar><span class=secno>10.1. </span>Grammar</h3>

  <p>The grammar below defines the syntax of Selectors. It is globally LL(1)
   and can be locally LL(2) (but note that most UAs should not use it
   directly, since it doesn't express the parsing conventions). The format of
   the productions is optimized for human consumption and some shorthand
   notations beyond Yacc (see <a href="#YACC"
   rel=biblioentry>[YACC]<!--{{!YACC}}--></a>) are used:

  <ul>
   <li><b>*</b>: 0 or more

   <li><b>+</b>: 1 or more

   <li><b>?</b>: 0 or 1

   <li><b>|</b>: separates alternatives

   <li><b>[ ]</b>: grouping
  </ul>

  <p>The productions are:

  <pre>selectors_group
  : selector [ COMMA S* selector ]*
  ;

selector
  : simple_selector_sequence [ combinator simple_selector_sequence ]*
  ;

combinator
  /* combinators can be surrounded by whitespace */
  : PLUS S* | GREATER S* | TILDE S* | S+
  ;

simple_selector_sequence
  : [ type_selector | universal ]
    [ HASH | class | attrib | pseudo | negation ]*
  | [ HASH | class | attrib | pseudo | negation ]+
  ;

type_selector
  : [ namespace_prefix ]? element_name
  ;

namespace_prefix
  : [ IDENT | '*' ]? '|'
  ;

element_name
  : IDENT
  ;

universal
  : [ namespace_prefix ]? '*'
  ;

class
  : '.' IDENT
  ;

attrib
  : '[' S* [ namespace_prefix ]? IDENT S*
        [ [ PREFIXMATCH |
            SUFFIXMATCH |
            SUBSTRINGMATCH |
            '=' |
            INCLUDES |
            DASHMATCH ] S* [ IDENT | STRING ] S*
        ]? ']'
  ;

pseudo
  /* '::' starts a pseudo-element, ':' a pseudo-class */
  /* Exceptions: :first-line, :first-letter, :before and :after. */
  /* Note that pseudo-elements are restricted to one per selector and */
  /* occur only in the last simple_selector_sequence. */
  : ':' ':'? [ IDENT | functional_pseudo ]
  ;

functional_pseudo
  : FUNCTION S* expression ')'
  ;

expression
  /* In CSS3, the expressions are identifiers, strings, */
  /* or of the form "an+b" */
  : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
  ;

negation
  : NOT S* negation_arg S* ')'
  ;

negation_arg
  : type_selector | universal | HASH | class | attrib | pseudo
  ;</pre>

  <h3 id=lex><span class=secno>10.2. </span>Lexical scanner</h3>

  <p>The following is the <a name=x3>tokenizer</a>, written in Flex (see <a
   href="#FLEX" rel=biblioentry>[FLEX]<!--{{!FLEX}}--></a>) notation. The
   tokenizer is case-insensitive.

  <p>The two occurrences of "\377" represent the highest character number
   that current versions of Flex can deal with (decimal 255). They should be
   read as "\4177777" (decimal 1114111), which is the highest possible code
   point in Unicode/ISO-10646. <a href="#UNICODE"
   rel=biblioentry>[UNICODE]<!--{{!UNICODE}}--></a>

  <pre>%option case-insensitive

ident     [-]?{nmstart}{nmchar}*
name      {nmchar}+
nmstart   [_a-z]|{nonascii}|{escape}
nonascii  [^\0-\177]
unicode   \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
escape    {unicode}|\\[^\n\r\f0-9a-f]
nmchar    [_a-z0-9-]|{nonascii}|{escape}
num       [0-9]+|[0-9]*\.[0-9]+
string    {string1}|{string2}
string1   \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*\"
string2   \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\'
invalid   {invalid1}|{invalid2}
invalid1  \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*
invalid2  \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*
nl        \n|\r\n|\r|\f
w         [ \t\r\n\f]*

D         d|\\0{0,4}(44|64)(\r\n|[ \t\r\n\f])?
E         e|\\0{0,4}(45|65)(\r\n|[ \t\r\n\f])?
N         n|\\0{0,4}(4e|6e)(\r\n|[ \t\r\n\f])?|\\n
O         o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o
T         t|\\0{0,4}(54|74)(\r\n|[ \t\r\n\f])?|\\t
V         v|\\0{0,4}(58|78)(\r\n|[ \t\r\n\f])?|\\v

%%

[ \t\r\n\f]+     return S;

"~="             return INCLUDES;
"|="             return DASHMATCH;
"^="             return PREFIXMATCH;
"$="             return SUFFIXMATCH;
"*="             return SUBSTRINGMATCH;
{ident}          return IDENT;
{string}         return STRING;
{ident}"("       return FUNCTION;
{num}            return NUMBER;
"#"{name}        return HASH;
{w}"+"           return PLUS;
{w}"&gt;"           return GREATER;
{w}","           return COMMA;
{w}"~"           return TILDE;
":"{N}{O}{T}"("  return NOT;
@{ident}         return ATKEYWORD;
{invalid}        return INVALID;
{num}%           return PERCENTAGE;
{num}{ident}     return DIMENSION;
"&lt;!--"           return CDO;
"--&gt;"            return CDC;

\/\*[^*]*\*+([^/*][^*]*\*+)*\/                    /* ignore comments */

.                return *yytext;</pre>

  <h2 id=profiling><span class=secno>11. </span>Profiles</h2>

  <p>Each specification using Selectors must define the subset of Selectors
   it allows and excludes, and describe the local meaning of all the
   components of that subset.

  <p>Non normative examples:

  <div class=profile>
   <table class=tprofile>
    <tbody>
     <tr>
      <th class=title colspan=2>Selectors profile

     <tr>
      <th>Specification

      <td>CSS level 1

     <tr>
      <th>Accepts

      <td>type selectors<br>
       class selectors<br>
       ID selectors<br>
       :link, :visited and :active pseudo-classes<br>
       descendant combinator <br>
       ::first-line and ::first-letter pseudo-elements

     <tr>
      <th>Excludes

      <td>
       <p>universal selector<br>
        attribute selectors<br>
        :hover and :focus pseudo-classes<br>
        :target pseudo-class<br>
        :lang() pseudo-class<br>
        all UI element states pseudo-classes<br>
        all structural pseudo-classes<br>
        negation pseudo-class<br>
        ::before and ::after pseudo-elements<br>
        child combinators<br>
        sibling combinators

       <p>namespaces

     <tr>
      <th>Extra constraints

      <td>only one class selector allowed per sequence of simple selectors
   </table>
   <br>
   <br>

   <table class=tprofile>
    <tbody>
     <tr>
      <th class=title colspan=2>Selectors profile

     <tr>
      <th>Specification

      <td>CSS level 2

     <tr>
      <th>Accepts

      <td>type selectors<br>
       universal selector<br>
       attribute presence and values selectors<br>
       class selectors<br>
       ID selectors<br>
       :link, :visited, :active, :hover, :focus, :lang() and :first-child
       pseudo-classes <br>
       descendant combinator<br>
       child combinator<br>
       adjacent sibling combinator<br>
       ::first-line and ::first-letter pseudo-elements<br>
       ::before and ::after pseudo-elements

     <tr>
      <th>Excludes

      <td>
       <p>substring matching attribute selectors<br>
        :target pseudo-classes<br>
        all UI element states pseudo-classes<br>
        all structural pseudo-classes other than :first-child<br>
        negation pseudo-class <br>
        general sibling combinators

       <p>namespaces

     <tr>
      <th>Extra constraints

      <td>more than one class selector per sequence of simple selectors (CSS1
       constraint) allowed
   </table>

   <p>In CSS, selectors express pattern matching rules that determine which
    style rules apply to elements in the document tree.

   <p>The following selector (CSS level 2) will <b>match</b> all anchors
    <code>a</code> with attribute <code>name</code> set inside a section 1
    header <code>h1</code>:

   <pre>h1 a[name]</pre>

   <p>All CSS declarations attached to such a selector are applied to
    elements matching it.
  </div>

  <div class=profile>
   <table class=tprofile>
    <tbody>
     <tr>
      <th class=title colspan=2>Selectors profile

     <tr>
      <th>Specification

      <td>STTS 3

     <tr>
      <th>Accepts

      <td>
       <p>type selectors<br>
        universal selectors<br>
        attribute selectors<br>
        class selectors<br>
        ID selectors<br>
        all structural pseudo-classes<br>
        all combinators

       <p>namespaces

     <tr>
      <th>Excludes

      <td>non-accepted pseudo-classes<br>
       pseudo-elements<br>

     <tr>
      <th>Extra constraints

      <td>some selectors and combinators are not allowed in fragment
       descriptions on the right side of STTS declarations.
   </table>

   <p>Selectors can be used in STTS 3 in two different manners:

   <ol>
    <li>a selection mechanism equivalent to CSS selection mechanism:
     declarations attached to a given selector are applied to elements
     matching that selector,

    <li>fragment descriptions that appear on the right side of declarations.
   </ol>
  </div>

  <h2 id=Conformance><span class=secno>12. </span>Conformance and
   requirements</h2>

  <p>This section defines conformance with the present specification only.

  <p>The inability of a user agent to implement part of this specification
   due to the limitations of a particular device (e.g., non interactive user
   agents will probably not implement dynamic pseudo-classes because they
   make no sense without interactivity) does not imply non-conformance.

  <p>All specifications reusing Selectors must contain a <a
   href="#profiling">Profile</a> listing the subset of Selectors it accepts
   or excludes, and describing the constraints it adds to the current
   specification.

  <p>Invalidity is caused by a parsing error, e.g. an unrecognized token or a
   token which is not allowed at the current parsing point.

  <p>User agents must observe the rules for handling parsing errors:

  <ul>
   <li>a simple selector containing an <a href="#nsdecl">undeclared namespace
    prefix</a> is invalid

   <li>a selector containing an invalid simple selector, an invalid
    combinator or an invalid token is invalid.

   <li>a group of selectors containing an invalid selector is invalid.
  </ul>

  <p>Specifications reusing Selectors must define how to handle parsing
   errors. (In the case of CSS, the entire rule in which the selector is used
   is dropped.)

  <h2 id=Tests><span class=secno>13. </span>Tests</h2>

  <p>This specification has <a
   href="http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/">a test
   suite</a> allowing user agents to verify their basic conformance to the
   specification. This test suite does not pretend to be exhaustive and does
   not cover all possible combined cases of Selectors.

  <h2 id=ACKS><span class=secno>14. </span>Acknowledgements</h2>

  <p>The CSS working group would like to thank everyone who has sent comments
   on this specification over the years.

  <p>In particular, the working group would like to extend special thanks to
   Donna McManus, Justin Baker, Joel Sklar, and Molly Ives Brower who
   performed the final editorial review of the last call draft. The working
   group would also like to thank Adam Kuehn, Boris Zbarsky, David Perrell,
   Elliotte Harold, Matthew Raymond, Ruud Steltenpool, Patrick Garies, Anton
   Prowse, and the W3C Internationalization Working Group for their last call
   comments and kind words.

  <h2 id=references><span class=secno>15. </span>References</h2>

  <h3 id=normative-references><span class=secno>15.1. </span>Normative
   References</h3>
  <!--begin-normative-->
  <!-- Sorted by label -->

  <dl class=bibliography>
   <dt style="display: none"><!-- keeps the doc valid if the DL is empty -->
    <!---->

   <dt id=CSS21>[CSS21]

   <dd>Bert Bos; et al. <a
    href="http://www.w3.org/TR/2009/CR-CSS2-20090908"><cite>Cascading Style
    Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 07 June 2011. W3C Recommendation.  URL: <a
    href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">http://www.w3.org/TR/2011/REC-CSS2-20110607/</a>
    </dd>
   <!---->

   <dt id=CSS3NAMESPACE>[CSS3NAMESPACE]

   <dd>Elika J. Etemad; Anne van Kesteren. <a
    href="http://www.w3.org/TR/2011/REC-css3-namespace-20110929/"><cite>CSS
    Namespaces Module.</cite></a> 29 September 2011. W3C Recommendation.
    URL: <a
    href="http://www.w3.org/TR/2011/REC-css3-namespace-20110929/">http://www.w3.org/TR/2011/REC-css3-namespace-20110929/</a>
    </dd>
   <!---->

   <dt id=FLEX>[FLEX]

   <dd><cite>Flex: The Lexical Scanner Generator.</cite> Version 2.3.7, ISBN
    1882114213</dd>
   <!---->

   <dt id=UNICODE>[UNICODE]

<dd>The Unicode Consortium. The
Unicode Standard, Version 6.0.0, (Mountain View, CA: The Unicode
Consortium, 2011. ISBN 978-1-936213-01-6)
and as updated from time to time by the publication
of new versions. (See <a href="http://www.unicode.org/unicode/standard/versions/">
http://www.unicode.org/unicode/standard/versions/</a> for the latest
version and additional information on versions of the standard and of
the Unicode Character Database).<br> Available at <a href="http://www.unicode.org/versions/Unicode6.0.0/">
http://www.unicode.org/versions/Unicode6.0.0/</a>
    </dd>
   <!---->

   <dt id=YACC>[YACC]

   <dd>S. C. Johnson. <cite>YACC - Yet another compiler compiler.</cite>
    Murray Hill. 1975. Technical Report.</dd>
   <!---->
  </dl>
  <!--end-normative-->

  <h3 id=informative-references><span class=secno>15.2. </span>Informative
   References</h3>
  <!--begin-informative-->
  <!-- Sorted by label -->

  <dl class=bibliography>
   <dt style="display: none"><!-- keeps the doc valid if the DL is empty -->
    <!---->

   <dt id=BCP47>[BCP47]

   <dd>A. Phillips;  M. Davis<a
    href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt"><cite>Tags for Identifying Languages</cite> and <cite>Matching of Language Tags</cite>.</a> September 2009. Internet Best
    Current Practice 47. URL: <a
    href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt">http://www.rfc-editor.org/rfc/bcp/bcp47.txt</a>
    </dd>
   <!---->

   <dt id=CSS1>[CSS1]

   <dd>H&#229;kon Wium Lie; Bert Bos. <a
    href="http://www.w3.org/TR/2008/REC-CSS1-20080411"><cite>Cascading Style
    Sheets (CSS1) Level 1 Specification.</cite></a> 11 April 2008. W3C
    Recommendation. URL: <a
    href="http://www.w3.org/TR/2008/REC-CSS1-20080411">http://www.w3.org/TR/2008/REC-CSS1-20080411</a>
    </dd>
   <!---->

   <dt id=DOM-LEVEL-3-CORE>[DOM-LEVEL-3-CORE]

   <dd>Gavin Nicol; et al. <a
    href="http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407"><cite>Document
    Object Model (DOM) Level 3 Core Specification.</cite></a> 7 April 2004.
    W3C Recommendation. URL: <a
    href="http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407">http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407</a>
    </dd>
   <!---->

   <dt id=HTML401>[HTML401]

   <dd>David Raggett; Ian Jacobs; Arnaud Le Hors. <a
    href="http://www.w3.org/TR/1999/REC-html401-19991224"><cite>HTML 4.01
    Specification.</cite></a> 24 December 1999. W3C Recommendation. URL: <a
    href="http://www.w3.org/TR/1999/REC-html401-19991224">http://www.w3.org/TR/1999/REC-html401-19991224</a>
    </dd>
   <!---->

   <dt id=MATHML>[MATHML]

   <dd>Patrick Ion; Robert Miner. <a
    href="http://www.w3.org/1999/07/REC-MathML-19990707"><cite>Mathematical
    Markup Language (MathML) 1.01 Specification.</cite></a> 7 July 1999. W3C
    Recommendation. URL: <a
    href="http://www.w3.org/1999/07/REC-MathML-19990707">http://www.w3.org/1999/07/REC-MathML-19990707</a>
    </dd>
   <!---->

   <dt id=STTS3>[STTS3]

   <dd>Daniel Glazman. <a href="http://www.w3.org/TR/NOTE-STTS3"><cite>Simple
    Tree Transformation Sheets 3.</cite></a> Electricit&#233; de France. 11
    November 1998. Submission to the W3C. URL: <a
    href="http://www.w3.org/TR/NOTE-STTS3">http://www.w3.org/TR/NOTE-STTS3</a>
    </dd>
   <!---->

   <dt id=SVG11>[SVG11]

   <dd>Erik Dahlström et. al. <a
    href="http://www.w3.org/TR/2011/REC-SVG11-20110816/"><cite>Scalable Vector
    Graphics (SVG) 1.1 Specification.</cite></a> 16 August 2011. W3C
    Recommendation. URL: <a
    href="http://www.w3.org/TR/2011/REC-SVG11-20110816/">http://www.w3.org/TR/2011/REC-SVG11-20110816/</a>
    </dd>
   <!---->

   <dt id=UAX29>[UAX29]

   <dd>Mark Davis. <a
    href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html"><cite>Text
    Boundaries.</cite></a> 25 March 2005. Unicode Standard Annex #29. URL: <a
    href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html">http://www.unicode.org/unicode/reports/tr29/tr29-9.html</a>
    </dd>
   <!---->

   <dt id=XML-NAMES>[XML-NAMES]

   <dd>Tim Bray; et al. <a
    href="http://www.w3.org/TR/2009/PER-xml-names-20090806"><cite>Namespaces
    in XML 1.0 (Third Edition).</cite></a> 6 August 2009. W3C Proposed Edited
    Recommendation. URL: <a
    href="http://www.w3.org/TR/2009/PER-xml-names-20090806">http://www.w3.org/TR/2009/PER-xml-names-20090806</a>
    </dd>
   <!---->

   <dt id=XML10>[XML10]

   <dd>C. M. Sperberg-McQueen; et al. <a
    href="http://www.w3.org/TR/2008/PER-xml-20080205"><cite>Extensible Markup
    Language (XML) 1.0 (Fifth Edition).</cite></a> 10 February 1998. W3C
    Proposed Edited Recommendation. Revised 5 February 2008 URL: <a
    href="http://www.w3.org/TR/2008/PER-xml-20080205">http://www.w3.org/TR/2008/PER-xml-20080205</a>
    </dd>
   <!---->
  </dl>
  <!--end-informative-->