syntax.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en-US-x-Hixie" ><head><title>8 The HTML syntax — HTML5 </title><style type="text/css">
pre { margin-left: 2em; white-space: pre-wrap; }
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h5, h6 { margin: 2.5em 0 1em; }
h1 + h2, h1 + h2 + h2 { margin: 0.75em 0 0.75em; }
h2 + h3, h3 + h4, h4 + h5, h5 + h6 { margin-top: 0.5em; }
p { margin: 1em 0; }
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dt { margin-top: 0.75em; margin-bottom: 0.25em; clear: left; }
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dd p { margin-top: 0; }
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dd table + p { margin-top: 1em; }
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dt dfn { font-style: italic; }
pre, code { font-size: inherit; font-family: monospace; font-variant: normal; }
pre strong { color: black; font: inherit; font-weight: bold; background: yellow; }
pre em { font-weight: bolder; font-style: normal; }
@media screen { code { color: orangered; } code :link, code :visited { color: inherit; } }
var sub { vertical-align: bottom; font-size: smaller; position: relative; top: 0.1em; }
table { border-collapse: collapse; border-style: hidden hidden none hidden; }
table thead, table tbody { border-bottom: solid; }
table tbody th:first-child { border-left: solid; }
table tbody th { text-align: left; }
table td, table th { border-left: solid; border-right: solid; border-bottom: solid thin; vertical-align: top; padding: 0.2em; }
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.toc dfn, h1 dfn, h2 dfn, h3 dfn, h4 dfn, h5 dfn, h6 dfn { font: inherit; }
img.extra { float: right; }
pre.idl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; }
pre.idl :link, pre.idl :visited { color: inherit; background: transparent; }
pre.css { border: solid thin; background: #FFFFEE; color: black; padding: 0.5em 1em; }
pre.css:first-line { color: #AAAA50; }
dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
dl.domintro dd p { margin: 0.5em 0; }
dl.switch { padding-left: 2em; }
dl.switch > dt { text-indent: -1.5em; }
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dl.triple { padding: 0 0 0 1em; }
dl.triple dt, dl.triple dd { margin: 0; display: inline }
dl.triple dt:after { content: ':'; }
dl.triple dd:after { content: '\A'; white-space: pre; }
.diff-old { text-decoration: line-through; color: silver; background: transparent; }
.diff-chg, .diff-new { text-decoration: underline; color: green; background: transparent; }
a .diff-new { border-bottom: 1px blue solid; }
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div.head p { margin: 0; }
div.head h1 { margin: 0; }
div.head .logo { float: right; margin: 0 1em; }
div.head .logo img { border: none } /* remove border from top image */
div.head dl { margin: 1em 0; }
div.head p.copyright, div.head p.alt { font-size: x-small; font-style: oblique; margin: 0; }
body > .toc > li { margin-top: 1em; margin-bottom: 1em; }
body > .toc.brief > li { margin-top: 0.35em; margin-bottom: 0.35em; }
body > .toc > li > * { margin-bottom: 0.5em; }
body > .toc > li > * > li > * { margin-bottom: 0.25em; }
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.category-list li:not(:last-child)::after { content: ', '; }
.category-list li > span, .category-list li > a { text-transform: lowercase; }
.category-list li * { text-transform: none; } /* don't affect <code> nested in <a> */
.XXX { color: #E50000; background: white; border: solid red; padding: 0.5em; margin: 1em 0; }
.XXX > :first-child { margin-top: 0; }
p .XXX { line-height: 3em; }
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.annotation :link, .annotation :visited { color: inherit; }
.annotation :link:hover, .annotation :visited:hover { background: transparent; }
.annotation span { border: none ! important; }
.note { color: green; background: transparent; font-family: sans-serif; }
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.note, .warning { font-weight: bolder; font-style: italic; }
p.note, div.note { padding: 0.5em 2em; }
span.note { padding: 0 2em; }
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.warning:before { font-style: normal; }
p.note:before { content: 'Note: '; }
p.warning:before { content: '\26A0 Warning! '; }
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h4 { position: relative; z-index: 3; }
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.element {
background: #EEEEFF;
color: black;
margin: 0 0 1em 0.15em;
padding: 0 1em 0.25em 0.75em;
border-left: solid #9999FF 0.25em;
position: relative;
z-index: 1;
}
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position: absolute;
z-index: 2;
top: 0;
left: -1.15em;
height: 2em;
width: 0.9em;
background: #EEEEFF;
content: ' ';
border-style: none none solid solid;
border-color: #9999FF;
border-width: 0.25em;
}
.example { display: block; color: #222222; background: #FCFCFC; border-left: double; margin-left: 2em; padding-left: 1em; }
td > .example:only-child { margin: 0 0 0 0.1em; }
ul.domTree, ul.domTree ul { padding: 0 0 0 1em; margin: 0; }
ul.domTree li { padding: 0; margin: 0; list-style: none; position: relative; }
ul.domTree li li { list-style: none; }
ul.domTree li:first-child::before { position: absolute; top: 0; height: 0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
ul.domTree li:not(:last-child)::after { position: absolute; top: 0; bottom: -0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
ul.domTree span { font-style: italic; font-family: serif; }
ul.domTree .t1 code { color: purple; font-weight: bold; }
ul.domTree .t2 { font-style: normal; font-family: monospace; }
ul.domTree .t2 .name { color: black; font-weight: bold; }
ul.domTree .t2 .value { color: blue; font-weight: normal; }
ul.domTree .t3 code, .domTree .t4 code, .domTree .t5 code { color: gray; }
ul.domTree .t7 code, .domTree .t8 code { color: green; }
ul.domTree .t10 code { color: teal; }
body.dfnEnabled dfn { cursor: pointer; }
.dfnPanel {
display: inline;
position: absolute;
z-index: 10;
height: auto;
width: auto;
padding: 0.5em 0.75em;
font: small sans-serif, Droid Sans Fallback;
background: #DDDDDD;
color: black;
border: outset 0.2em;
}
.dfnPanel * { margin: 0; padding: 0; font: inherit; text-indent: 0; }
.dfnPanel :link, .dfnPanel :visited { color: black; }
.dfnPanel p { font-weight: bolder; }
.dfnPanel * + p { margin-top: 0.25em; }
.dfnPanel li { list-style-position: inside; }
#configUI { position: absolute; z-index: 20; top: 10em; right: 1em; width: 11em; font-size: small; }
#configUI p { margin: 0.5em 0; padding: 0.3em; background: #EEEEEE; color: black; border: inset thin; }
#configUI p label { display: block; }
#configUI #updateUI, #configUI .loginUI { text-align: center; }
#configUI input[type=button] { display: block; margin: auto; }
fieldset { margin: 1em; padding: 0.5em 1em; }
fieldset > legend + * { margin-top: 0; }
fieldset > :last-child { margin-bottom: 0; }
fieldset p { margin: 0.5em 0; }
.stability {
position: fixed;
bottom: 0;
left: 0; right: 0;
margin: 0 auto 0 auto !important;
z-index: 1000;
width: 50%;
background: maroon; color: yellow;
-webkit-border-radius: 1em 1em 0 0;
-moz-border-radius: 1em 1em 0 0;
border-radius: 1em 1em 0 0;
-moz-box-shadow: 0 0 1em #500;
-webkit-box-shadow: 0 0 1em #500;
box-shadow: 0 0 1em red;
padding: 0.5em 1em;
text-align: center;
}
.stability strong {
display: block;
}
.stability input {
appearance: none; margin: 0; border: 0; padding: 0.25em 0.5em; background: transparent; color: black;
position: absolute; top: -0.5em; right: 0; font: 1.25em sans-serif; text-align: center;
}
.stability input:hover {
color: white;
text-shadow: 0 0 2px black;
}
.stability input:active {
padding: 0.3em 0.45em 0.2em 0.55em;
}
.stability :link, .stability :visited,
.stability :link:hover, .stability :visited:hover {
background: transparent;
color: white;
}
</style><link href="data:text/css,.impl%20%7B%20display:%20none;%20%7D%0Ahtml%20%7B%20border:%20solid%20yellow;%20%7D%20.domintro:before%20%7B%20display:%20none;%20%7D" id="author" rel="alternate stylesheet" title="Author documentation only"><link href="data:text/css,.impl%20%7B%20background:%20%23FFEEEE;%20%7D%20.domintro:before%20%7B%20background:%20%23FFEEEE;%20%7D" id="highlight" rel="alternate stylesheet" title="Highlight implementation
requirements"><link href="http://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css"><style type="text/css">
.applies thead th > * { display: block; }
.applies thead code { display: block; }
.applies tbody th { whitespace: nowrap; }
.applies td { text-align: center; }
.applies .yes { background: yellow; }
.matrix, .matrix td { border: hidden; text-align: right; }
.matrix { margin-left: 2em; }
.dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
.dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
.dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
td.eg { border-width: thin; text-align: center; }
#table-example-1 { border: solid thin; border-collapse: collapse; margin-left: 3em; }
#table-example-1 * { font-family: "Essays1743", serif; line-height: 1.01em; }
#table-example-1 caption { padding-bottom: 0.5em; }
#table-example-1 thead, #table-example-1 tbody { border: none; }
#table-example-1 th, #table-example-1 td { border: solid thin; }
#table-example-1 th { font-weight: normal; }
#table-example-1 td { border-style: none solid; vertical-align: top; }
#table-example-1 th { padding: 0.5em; vertical-align: middle; text-align: center; }
#table-example-1 tbody tr:first-child td { padding-top: 0.5em; }
#table-example-1 tbody tr:last-child td { padding-bottom: 1.5em; }
#table-example-1 tbody td:first-child { padding-left: 2.5em; padding-right: 0; width: 9em; }
#table-example-1 tbody td:first-child::after { content: leader(". "); }
#table-example-1 tbody td { padding-left: 2em; padding-right: 2em; }
#table-example-1 tbody td:first-child + td { width: 10em; }
#table-example-1 tbody td:first-child + td ~ td { width: 2.5em; }
#table-example-1 tbody td:first-child + td + td + td ~ td { width: 1.25em; }
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column-width: 30em;
column-gap: 1em;
-moz-column-width: 30em;
-moz-column-gap: 1em;
-webkit-column-width: 30em;
-webkit-column-gap: 1em;
}
#named-character-references-table > table > tbody > tr > td:first-child + td,
#named-character-references-table > table > tbody > tr > td:last-child { text-align: center; }
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.glyph.control { color: red; }
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font-family: 'Essays1743';
src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743.ttf');
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}
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<p class="stability" id="wip"><strong>This is a work in
progress!</strong> For the latest updates from the HTML WG, possibly
including important bug fixes, please look at the <a href="http://dev.w3.org/html5/spec/Overview.html">editor's draft</a> instead.
There may also be a more
<a href="http://www.w3.org/TR/html5">up-to-date Working Draft</a>
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<h1>HTML5</h1>
</div><div>
<a href="dnd.html" class="prev">7.7 Drag and drop</a> –
<a href="spec.html#contents">Table of contents</a> –
<a href="parsing.html" class="next">8.2 Parsing HTML documents</a>
<ol class="toc"><li><a href="syntax.html#syntax"><span class="secno">8 </span>The HTML syntax</a>
<ol><li><a href="syntax.html#writing"><span class="secno">8.1 </span>Writing HTML documents</a>
<ol><li><a href="syntax.html#the-doctype"><span class="secno">8.1.1 </span>The DOCTYPE</a></li><li><a href="syntax.html#elements-0"><span class="secno">8.1.2 </span>Elements</a>
<ol><li><a href="syntax.html#start-tags"><span class="secno">8.1.2.1 </span>Start tags</a></li><li><a href="syntax.html#end-tags"><span class="secno">8.1.2.2 </span>End tags</a></li><li><a href="syntax.html#attributes-0"><span class="secno">8.1.2.3 </span>Attributes</a></li><li><a href="syntax.html#optional-tags"><span class="secno">8.1.2.4 </span>Optional tags</a></li><li><a href="syntax.html#element-restrictions"><span class="secno">8.1.2.5 </span>Restrictions on content models</a></li><li><a href="syntax.html#cdata-rcdata-restrictions"><span class="secno">8.1.2.6 </span>Restrictions on the contents of raw text and RCDATA elements</a></li></ol></li><li><a href="syntax.html#text-0"><span class="secno">8.1.3 </span>Text</a>
<ol><li><a href="syntax.html#newlines"><span class="secno">8.1.3.1 </span>Newlines</a></li></ol></li><li><a href="syntax.html#character-references"><span class="secno">8.1.4 </span>Character references</a></li><li><a href="syntax.html#cdata-sections"><span class="secno">8.1.5 </span>CDATA sections</a></li><li><a href="syntax.html#comments"><span class="secno">8.1.6 </span>Comments</a></li></ol></li></ol></li></ol></div>
<h2 id="syntax"><span class="secno">8 </span><dfn>The HTML syntax</dfn></h2><p class="note">This section only describes the rules for resources
labeled with an <a href="infrastructure.html#html-mime-type">HTML MIME type</a>. Rules for XML resources
are discussed in the section below entitled "<a href="the-xhtml-syntax.html#the-xhtml-syntax">The XHTML
syntax</a>".</p><h3 id="writing"><span class="secno">8.1 </span>Writing HTML documents</h3><div class="impl">
<p><i>This section only applies to documents, authoring tools, and
markup generators. In particular, it does not apply to conformance
checkers; conformance checkers must use the requirements given in
the next section ("parsing HTML documents").</i></p>
</div><p>Documents must consist of the following parts, in the given
order:</p><ol><li>Optionally, a single U+FEFF BYTE ORDER MARK (BOM) character.</li>
<li>Any number of <a href="#syntax-comments" title="syntax-comments">comments</a> and
<a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A <a href="#syntax-doctype" title="syntax-doctype">DOCTYPE</a>.
</li><li>Any number of <a href="#syntax-comments" title="syntax-comments">comments</a> and
<a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>The root element, in the form of an <code><a href="semantics.html#the-html-element">html</a></code> <a href="#syntax-elements" title="syntax-elements">element</a>.</li>
<li>Any number of <a href="#syntax-comments" title="syntax-comments">comments</a> and
<a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
</ol><p>The various types of content mentioned above are described in the
next few sections.</p><p>In addition, there are some restrictions on how <a href="semantics.html#character-encoding-declaration" title="character encoding declaration">character encoding
declarations</a> are to be serialized, as discussed in the
section on that topic.</p><div class="note">
<p>Space characters before the root <code><a href="semantics.html#the-html-element">html</a></code> element, and
space characters at the start of the <code><a href="semantics.html#the-html-element">html</a></code> element and
before the <code><a href="semantics.html#the-head-element">head</a></code> element, will be dropped when the
document is parsed; space characters <em>after</em> the root
<code><a href="semantics.html#the-html-element">html</a></code> element will be parsed as if they were at the end
of the <code><a href="sections.html#the-body-element">body</a></code> element. Thus, space characters around the
root element do not round-trip.</p>
<p>It is suggested that newlines be inserted after the DOCTYPE,
after any comments that are before the root element, after the
<code><a href="semantics.html#the-html-element">html</a></code> element's start tag (if it is not <a href="#syntax-tag-omission" title="syntax-tag-omission">omitted</a>), and after any comments
that are inside the <code><a href="semantics.html#the-html-element">html</a></code> element but before the
<code><a href="semantics.html#the-head-element">head</a></code> element.</p>
</div><p>Many strings in the HTML syntax (e.g. the names of elements and
their attributes) are case-insensitive, but only for characters in
the ranges U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL
LETTER Z) and U+0061 to U+007A (LATIN SMALL LETTER A to LATIN SMALL
LETTER Z). For convenience, in this section this is just referred to
as "case-insensitive".</p><h4 id="the-doctype"><span class="secno">8.1.1 </span>The DOCTYPE</h4><p>A <dfn id="syntax-doctype" title="syntax-doctype">DOCTYPE</dfn> is a required preamble.</p><p class="note">DOCTYPEs are required for legacy reasons. When
omitted, browsers tend to use a different rendering mode that is
incompatible with some specifications. Including the DOCTYPE in a
document ensures that the browser makes a best-effort attempt at
following the relevant specifications.</p><p>A DOCTYPE must consist of the following components, in this
order:</p><ol class="brief"><li>A string that is an <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for the string "<code title=""><!DOCTYPE</code>".</li>
<li>One or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A string that is an <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for the string "<code title="">html</code>".</li>
<li>Optionally, a <a href="#doctype-legacy-string">DOCTYPE legacy string</a> or an <a href="#obsolete-permitted-doctype-string">obsolete permitted DOCTYPE string</a> (defined below).</li>
<li>Zero or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A U+003E GREATER-THAN SIGN character (>).</li>
</ol><p class="note">In other words, <code><!DOCTYPE html></code>,
case-insensitively.</p><hr><p>For the purposes of HTML generators that cannot output HTML
markup with the short DOCTYPE "<code title=""><!DOCTYPE
html></code>", a <dfn id="doctype-legacy-string">DOCTYPE legacy string</dfn> may be inserted
into the DOCTYPE (in the position defined above). This string must
consist of:</p><ol class="brief"><li>One or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A string that is an <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for the string "<code title="">SYSTEM</code>".</li>
<li>One or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (the <i>quote mark</i>).</li>
<li>The literal string "<code><a href="urls.html#about:legacy-compat">about:legacy-compat</a></code>".</li>
<li>A matching U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (i.e. the same character as in the earlier step labeled <i>quote mark</i>).</li>
</ol><p class="note">In other words, <code><!DOCTYPE html SYSTEM
"about:legacy-compat"></code> or <code><!DOCTYPE html SYSTEM
'about:legacy-compat'></code>, case-insensitively except for the
part in single or double quotes.</p><p>The <a href="#doctype-legacy-string">DOCTYPE legacy string</a> should not be used unless
the document is generated from a system that cannot output the
shorter string.</p><hr><p>To help authors transition from HTML4 and XHTML1, an
<dfn id="obsolete-permitted-doctype-string">obsolete permitted DOCTYPE string</dfn> can be inserted into
the DOCTYPE (in the position defined above). This string must
consist of:</p><ol class="brief"><li>One or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A string that is an <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for the string "<code title="">PUBLIC</code>".</li>
<li>One or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>A U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (the <i>first quote mark</i>).</li>
<li>The string from one of the cells in the first column of the table below. The row to which this cell belongs is the <i>selected row</i>.</li>
<li>A matching U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (i.e. the same character as in the earlier step labeled <i>first quote mark</i>).</li>
<li>If the cell in the second column of the <i>selected row</i> is not blank, one or more <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>If the cell in the second column of the <i>selected row</i> is not blank, a U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (the <i>third quote mark</i>).</li>
<li>If the cell in the second column of the <i>selected row</i> is not blank, the string from the cell in the second column of the <i>selected row</i>.</li>
<li>If the cell in the second column of the <i>selected row</i> is not blank, a matching U+0022 QUOTATION MARK or U+0027 APOSTROPHE character (i.e. the same character as in the earlier step labeled <i>third quote mark</i>).</li>
</ol><table><caption>
Allowed values for public and system identifiers in an <a href="#obsolete-permitted-doctype-string">obsolete permitted DOCTYPE string</a>.
</caption>
<thead><tr><th> Public identifier
</th><th> System identifier
</th></tr></thead><tbody><tr><td> <code title="">-//W3C//DTD HTML 4.0//EN</code>
</td><td>
</td></tr><tr><td> <code title="">-//W3C//DTD HTML 4.0//EN</code>
</td><td> <code title="">http://www.w3.org/TR/REC-html40/strict.dtd</code>
</td></tr><tr><td> <code title="">-//W3C//DTD HTML 4.01//EN</code>
</td><td>
</td></tr><tr><td> <code title="">-//W3C//DTD HTML 4.01//EN</code>
</td><td> <code title="">http://www.w3.org/TR/html4/strict.dtd</code>
</td></tr><tr><td> <code title="">-//W3C//DTD XHTML 1.0 Strict//EN</code>
</td><td> <code title="">http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd</code>
</td></tr><tr><td> <code title="">-//W3C//DTD XHTML 1.1//EN</code>
</td><td> <code title="">http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd</code>
</td></tr></tbody></table><p>A <a href="#syntax-doctype" title="syntax-doctype">DOCTYPE</a> containing an
<a href="#obsolete-permitted-doctype-string">obsolete permitted DOCTYPE string</a> is an <dfn id="obsolete-permitted-doctype">obsolete
permitted DOCTYPE</dfn>. Authors should not use <a href="#obsolete-permitted-doctype" title="obsolete permitted DOCTYPE">obsolete permitted
DOCTYPEs</a>, as they are unnecessarily long.</p><h4 id="elements-0"><span class="secno">8.1.2 </span>Elements</h4><p>There are five different kinds of <dfn id="syntax-elements" title="syntax-elements">elements</dfn>: <a href="#void-elements">void elements</a>,
<a href="#raw-text-elements">raw text elements</a>, <a href="#rcdata-elements">RCDATA elements</a>,
<a href="#foreign-elements">foreign elements</a>, and <a href="#normal-elements">normal elements</a>.</p><dl><dt><dfn id="void-elements">Void elements</dfn></dt>
<dd><code><a href="the-map-element.html#the-area-element">area</a></code>, <code><a href="semantics.html#the-base-element">base</a></code>, <code><a href="text-level-semantics.html#the-br-element">br</a></code>,
<code><a href="tabular-data.html#the-col-element">col</a></code>, <code><a href="interactive-elements.html#the-command-element">command</a></code>, <code><a href="the-iframe-element.html#the-embed-element">embed</a></code>,
<code><a href="grouping-content.html#the-hr-element">hr</a></code>, <code><a href="embedded-content-1.html#the-img-element">img</a></code>, <code><a href="the-input-element.html#the-input-element">input</a></code>,
<code><a href="the-button-element.html#the-keygen-element">keygen</a></code>, <code><a href="semantics.html#the-link-element">link</a></code>, <code><a href="semantics.html#the-meta-element">meta</a></code>,
<code><a href="the-iframe-element.html#the-param-element">param</a></code>, <code><a href="the-iframe-element.html#the-source-element">source</a></code>, <code><a href="the-iframe-element.html#the-track-element">track</a></code>,
<code><a href="text-level-semantics.html#the-wbr-element">wbr</a></code></dd>
<dt><dfn id="raw-text-elements">Raw text elements</dfn></dt>
<dd><code><a href="scripting-1.html#the-script-element">script</a></code>, <code><a href="semantics.html#the-style-element">style</a></code></dd>
<dt><dfn id="rcdata-elements">RCDATA elements</dfn></dt>
<dd><code><a href="the-button-element.html#the-textarea-element">textarea</a></code>, <code><a href="semantics.html#the-title-element">title</a></code></dd>
<dt><dfn id="foreign-elements">Foreign elements</dfn></dt>
<dd>Elements from the <a href="namespaces.html#mathml-namespace">MathML namespace</a>
and the <a href="namespaces.html#svg-namespace">SVG namespace</a>.</dd>
<dt><dfn id="normal-elements">Normal elements</dfn></dt>
<dd>All other allowed <a href="infrastructure.html#html-elements">HTML elements</a> are normal
elements.</dd>
</dl><p><dfn id="syntax-tags" title="syntax-tags">Tags</dfn> are used to delimit the start
and end of elements in the markup. <a href="#raw-text-elements" title="raw text
elements">Raw text</a>, <a href="#rcdata-elements" title="RCDATA
elements">RCDATA</a>, and <a href="#normal-elements" title="normal
elements">normal</a> elements have a <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> to indicate where they
begin, and an <a href="#syntax-end-tag" title="syntax-end-tag">end tag</a> to
indicate where they end. The start and end tags of certain
<a href="#normal-elements">normal elements</a> can be <a href="#syntax-tag-omission" title="syntax-tag-omission">omitted</a>, as described
later. Those that cannot be omitted must not be omitted. <a href="#void-elements">Void
elements</a> only have a start tag; end tags must not be
specified for <a href="#void-elements">void elements</a>. <a href="#foreign-elements">Foreign
elements</a> must either have a start tag and an end tag, or a
start tag that is marked as self-closing, in which case they must
not have an end tag.</p><p>The contents of the element must be placed between just after the
start tag (which <a href="#syntax-tag-omission" title="syntax-tag-omission">might be implied,
in certain cases</a>) and just before the end tag (which again,
<a href="#syntax-tag-omission" title="syntax-tag-omission">might be implied in certain
cases</a>). The exact allowed contents of each individual element
depend on the content model of that element, as described earlier in
this specification. Elements must not contain content that their
content model disallows. In addition to the restrictions placed on
the contents by those content models, however, the five types of
elements have additional <em>syntactic</em> requirements.</p><p><a href="#void-elements">Void elements</a> can't have any contents (since there's
no end tag, no content can be put between the start tag and the end
tag).</p><p><a href="#raw-text-elements">Raw text elements</a> can have <a href="#syntax-text" title="syntax-text">text</a>, though it has <a href="#cdata-rcdata-restrictions">restrictions</a> described
below.</p><p><a href="#rcdata-elements">RCDATA elements</a> can have <a href="#syntax-text" title="syntax-text">text</a> and <a href="#syntax-charref" title="syntax-charref">character references</a>, but the text
must not contain an <a href="#syntax-ambiguous-ampersand" title="syntax-ambiguous-ampersand">ambiguous ampersand</a>.
There are also <a href="#cdata-rcdata-restrictions">further
restrictions</a> described below.</p><p><a href="#foreign-elements">Foreign elements</a> whose start tag is marked as
self-closing can't have any contents (since, again, as there's no
end tag, no content can be put between the start tag and the end
tag). <a href="#foreign-elements">Foreign elements</a> whose start tag is <em>not</em>
marked as self-closing can have <a href="#syntax-text" title="syntax-text">text</a>, <a href="#syntax-charref" title="syntax-charref">character references</a>, <a href="#syntax-cdata" title="syntax-cdata">CDATA sections</a>, other <a href="#syntax-elements" title="syntax-elements">elements</a>, and <a href="#syntax-comments" title="syntax-comments">comments</a>, but the text must not
contain the character U+003C LESS-THAN SIGN (<) or an <a href="#syntax-ambiguous-ampersand" title="syntax-ambiguous-ampersand">ambiguous ampersand</a>.</p><div class="note">
<p>The HTML syntax does not support namespace
declarations, even in <a href="#foreign-elements">foreign elements</a>.</p>
<p>For instance, consider the following HTML fragment:</p>
<pre><p>
<svg>
<metadata>
<!-- this is invalid -->
<cdr:license xmlns:cdr="http://www.example.com/cdr/metadata" name="MIT"/>
</metadata>
</svg>
</p></pre>
<p>The innermost element, <code title="">cdr:license</code>, is
actually in the SVG namespace, as the "<code title="">xmlns:cdr</code>" attribute has no effect (unlike in
XML). In fact, as the comment in the fragment above says, the
fragment is actually non-conforming. This is because the SVG
specification does not define any elements called "<code title="">cdr:license</code>" in the SVG namespace.</p>
</div><p><a href="#normal-elements">Normal elements</a> can have <a href="#syntax-text" title="syntax-text">text</a>, <a href="#syntax-charref" title="syntax-charref">character references</a>, other <a href="#syntax-elements" title="syntax-elements">elements</a>, and <a href="#syntax-comments" title="syntax-comments">comments</a>, but the text must not
contain the character U+003C LESS-THAN SIGN (<) or an <a href="#syntax-ambiguous-ampersand" title="syntax-ambiguous-ampersand">ambiguous ampersand</a>. Some
<a href="#normal-elements">normal elements</a> also have <a href="#element-restrictions">yet more restrictions</a> on what
content they are allowed to hold, beyond the restrictions imposed by
the content model and those described in this paragraph. Those
restrictions are described below.</p><p>Tags contain a <dfn id="syntax-tag-name" title="syntax-tag-name">tag name</dfn>,
giving the element's name. HTML elements all have names that only
use characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT
NINE (9), U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER
Z, and U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER
Z. In the HTML syntax, tag names, even those for <a href="#foreign-elements">foreign
elements</a>, may be written with any mix of lower- and uppercase
letters that, when converted to all-lowercase, matches the element's
tag name; tag names are case-insensitive.</p><h5 id="start-tags"><span class="secno">8.1.2.1 </span>Start tags</h5><p><dfn id="syntax-start-tag" title="syntax-start-tag">Start tags</dfn> must have the
following format:</p><ol><li>The first character of a start tag must be a U+003C LESS-THAN
SIGN character (<).</li>
<li>The next few characters of a start tag must be the element's
<a href="#syntax-tag-name" title="syntax-tag-name">tag name</a>.</li>
<li>If there are to be any attributes in the next step, there must
first be one or more <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>.</li>
<li>Then, the start tag may have a number of attributes, the <a href="#syntax-attributes" title="syntax-attributes">syntax for which</a> is described
below. Attributes must be separated from each other by one or more
<a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
<li>After the attributes, or after the <a href="#syntax-tag-name" title="syntax-tag-name">tag name</a> if there are no attributes,
there may be one or more <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>. (Some attributes are required to be followed by
a space. See the <a href="#syntax-attributes" title="syntax-attributes">attributes
section</a> below.)</li>
<li>Then, if the element is one of the <a href="#void-elements">void elements</a>,
or if the element is a <a href="#foreign-elements" title="foreign elements">foreign
element</a>, then there may be a single U+002F SOLIDUS character
(/). This character has no effect on <a href="#void-elements">void elements</a>,
but on <a href="#foreign-elements">foreign elements</a> it marks the start tag as
self-closing.</li>
<li>Finally, start tags must be closed by a U+003E GREATER-THAN
SIGN character (>).</li>
</ol><h5 id="end-tags"><span class="secno">8.1.2.2 </span>End tags</h5><p><dfn id="syntax-end-tag" title="syntax-end-tag">End tags</dfn> must have the
following format:</p><ol><li>The first character of an end tag must be a U+003C LESS-THAN
SIGN character (<).</li>
<li>The second character of an end tag must be a U+002F SOLIDUS
character (/).</li>
<li>The next few characters of an end tag must be the element's
<a href="#syntax-tag-name" title="syntax-tag-name">tag name</a>.</li>
<li>After the tag name, there may be one or more <a href="common-microsyntaxes.html#space-character" title="space
character">space characters</a>.</li>
<li>Finally, end tags must be closed by a U+003E GREATER-THAN SIGN
character (>).</li>
</ol><h5 id="attributes-0"><span class="secno">8.1.2.3 </span>Attributes</h5><p><dfn id="syntax-attributes" title="syntax-attributes">Attributes</dfn> for an element
are expressed inside the element's start tag.</p><p>Attributes have a name and a value. <dfn id="syntax-attribute-name" title="syntax-attribute-name">Attribute names</dfn> must consist of
one or more characters other than the <a href="common-microsyntaxes.html#space-character" title="space
character">space characters</a>, U+0000 NULL, U+0022 QUOTATION
MARK ("), U+0027 APOSTROPHE ('), U+003E GREATER-THAN SIGN
(>), U+002F SOLIDUS (/), and U+003D EQUALS SIGN (=) characters,
the control characters, and any characters that are not defined by
Unicode. In the HTML syntax, attribute names, even those for
<a href="#foreign-elements">foreign elements</a>, may be written with any mix of lower-
and uppercase letters that are an <a href="infrastructure.html#ascii-case-insensitive">ASCII
case-insensitive</a> match for the attribute's name.</p><p><dfn id="syntax-attribute-value" title="syntax-attribute-value">Attribute values</dfn> are a
mixture of <a href="#syntax-text" title="syntax-text">text</a> and <a href="#syntax-charref" title="syntax-charref">character references</a>, except with the
additional restriction that the text cannot contain an <a href="#syntax-ambiguous-ampersand" title="syntax-ambiguous-ampersand">ambiguous ampersand</a>.</p><p>Attributes can be specified in four different ways:</p><dl><dt>Empty attribute syntax</dt>
<dd>
<p>Just the <a href="#syntax-attribute-name" title="syntax-attribute-name">attribute
name</a>. The value is implicitly the empty string.</p>
<div class="example">
<p>In the following example, the <code title="attr-fe-disabled"><a href="association-of-controls-and-forms.html#attr-fe-disabled">disabled</a></code> attribute is given with
the empty attribute syntax:</p>
<pre><input <em>disabled</em>></pre>
</div>
<p>If an attribute using the empty attribute syntax is to be
followed by another attribute, then there must be a <a href="common-microsyntaxes.html#space-character">space
character</a> separating the two.</p>
</dd>
<dt id="unquoted">Unquoted attribute value syntax</dt>
<dd>
<p>The <a href="#syntax-attribute-name" title="syntax-attribute-name">attribute name</a>,
followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>, followed by a single U+003D EQUALS SIGN
character, followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space
character">space characters</a>, followed by the <a href="#syntax-attribute-value" title="syntax-attribute-value">attribute value</a>, which, in
addition to the requirements given above for attribute values,
must not contain any literal <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>, any U+0022 QUOTATION MARK characters ("),
U+0027 APOSTROPHE characters ('), U+003D EQUALS SIGN
characters (=), U+003C LESS-THAN SIGN characters (<), U+003E
GREATER-THAN SIGN characters (>), or U+0060 GRAVE ACCENT
characters (`), and must not be the empty string.</p>
<div class="example">
<p>In the following example, the <code title="attr-input-value"><a href="the-input-element.html#attr-input-value">value</a></code> attribute is given
with the unquoted attribute value syntax:</p>
<pre><input <em>value=yes</em>></pre>
</div>
<p>If an attribute using the unquoted attribute syntax is to be
followed by another attribute or by the optional U+002F SOLIDUS
character (/) allowed in step 6 of the <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> syntax above, then there
must be a <a href="common-microsyntaxes.html#space-character">space character</a> separating the two.</p>
</dd>
<dt>Single-quoted attribute value syntax</dt>
<dd>
<p>The <a href="#syntax-attribute-name" title="syntax-attribute-name">attribute name</a>,
followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>, followed by a single U+003D EQUALS SIGN
character, followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space
character">space characters</a>, followed by a single U+0027
APOSTROPHE character ('), followed by the <a href="#syntax-attribute-value" title="syntax-attribute-value">attribute value</a>, which, in
addition to the requirements given above for attribute values,
must not contain any literal U+0027 APOSTROPHE characters ('), and
finally followed by a second single U+0027 APOSTROPHE character
(').</p>
<div class="example">
<p>In the following example, the <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute is given with the
single-quoted attribute value syntax:</p>
<pre><input <em>type='checkbox'</em>></pre>
</div>
<p>If an attribute using the single-quoted attribute syntax is to
be followed by another attribute, then there must be a <a href="common-microsyntaxes.html#space-character">space
character</a> separating the two.</p>
</dd>
<dt>Double-quoted attribute value syntax</dt>
<dd>
<p>The <a href="#syntax-attribute-name" title="syntax-attribute-name">attribute name</a>,
followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>, followed by a single U+003D EQUALS SIGN
character, followed by zero or more <a href="common-microsyntaxes.html#space-character" title="space
character">space characters</a>, followed by a single U+0022
QUOTATION MARK character ("), followed by the <a href="#syntax-attribute-value" title="syntax-attribute-value">attribute value</a>, which, in
addition to the requirements given above for attribute values,
must not contain any literal U+0022 QUOTATION MARK characters ("),
and finally followed by a second single U+0022 QUOTATION MARK
character (").</p>
<div class="example">
<p>In the following example, the <code title="attr-fe-name"><a href="association-of-controls-and-forms.html#attr-fe-name">name</a></code> attribute is given with the
double-quoted attribute value syntax:</p>
<pre><input <em>name="be evil"</em>></pre>
</div>
<p>If an attribute using the double-quoted attribute syntax is to
be followed by another attribute, then there must be a <a href="common-microsyntaxes.html#space-character">space
character</a> separating the two.</p>
</dd>
</dl><p>There must never be two or more attributes on the same start tag
whose names are an <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for
each other.</p><hr><p>When a <a href="#foreign-elements" title="foreign elements">foreign element</a> has
one of the namespaced attributes given by the local name and
namespace of the first and second cells of a row from the following
table, it must be written using the name given by the third cell
from the same row.</p><table><thead><tr><th> Local name </th><th> Namespace </th><th> Attribute name
</th></tr></thead><tbody><tr><td> <code title="">actuate</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:actuate</code>
</td></tr><tr><td> <code title="">arcrole</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:arcrole</code>
</td></tr><tr><td> <code title="">href</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:href</code>
</td></tr><tr><td> <code title="">role</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:role</code>
</td></tr><tr><td> <code title="">show</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:show</code>
</td></tr><tr><td> <code title="">title</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:title</code>
</td></tr><tr><td> <code title="">type</code> </td><td> <a href="namespaces.html#xlink-namespace">XLink namespace</a> </td><td> <code title="">xlink:type</code>
</td></tr><tr><td> <code title="">base</code> </td><td> <a href="namespaces.html#xml-namespace">XML namespace</a> </td><td> <code title="">xml:base</code>
</td></tr><tr><td> <code title="">lang</code> </td><td> <a href="namespaces.html#xml-namespace">XML namespace</a> </td><td> <code title="">xml:lang</code>
</td></tr><tr><td> <code title="">space</code> </td><td> <a href="namespaces.html#xml-namespace">XML namespace</a> </td><td> <code title="">xml:space</code>
</td></tr><tr><td> <code title="">xmlns</code> </td><td> <a href="namespaces.html#xmlns-namespace">XMLNS namespace</a> </td><td> <code title="">xmlns</code>
</td></tr><tr><td> <code title="">xlink</code> </td><td> <a href="namespaces.html#xmlns-namespace">XMLNS namespace</a> </td><td> <code title="">xmlns:xlink</code>
</td></tr></tbody></table><p>No other namespaced attribute can be expressed in <a href="#syntax">the
HTML syntax</a>.</p><h5 id="optional-tags"><span class="secno">8.1.2.4 </span>Optional tags</h5><p>Certain tags can be <dfn id="syntax-tag-omission" title="syntax-tag-omission">omitted</dfn>.</p><p class="note">Omitting an element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> does not mean the element
is not present; it is implied, but it is still there. An HTML
document always has a root <code><a href="semantics.html#the-html-element">html</a></code> element, even if the
string <code title=""><html></code> doesn't appear anywhere in
the markup.</p><p>An <code><a href="semantics.html#the-html-element">html</a></code> element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> may be omitted if the
first thing inside the <code><a href="semantics.html#the-html-element">html</a></code> element is not a <a href="#syntax-comments" title="syntax-comments">comment</a>.</p><p>An <code><a href="semantics.html#the-html-element">html</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="semantics.html#the-html-element">html</a></code> element is not
immediately followed by a <a href="#syntax-comments" title="syntax-comments">comment</a>.</p><p>A <code><a href="semantics.html#the-head-element">head</a></code> element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> may be omitted if the
element is empty, or if the first thing inside the
<code><a href="semantics.html#the-head-element">head</a></code> element is an element.</p><p>A <code><a href="semantics.html#the-head-element">head</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="semantics.html#the-head-element">head</a></code> element is not
immediately followed by a <a href="common-microsyntaxes.html#space-character">space character</a> or a <a href="#syntax-comments" title="syntax-comments">comment</a>.</p><p>A <code><a href="sections.html#the-body-element">body</a></code> element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> may be omitted if the
element is empty, or if the first thing inside the <code><a href="sections.html#the-body-element">body</a></code>
element is not a <a href="common-microsyntaxes.html#space-character">space character</a> or a <a href="#syntax-comments" title="syntax-comments">comment</a>, except if the first thing
inside the <code><a href="sections.html#the-body-element">body</a></code> element is a <code><a href="scripting-1.html#the-script-element">script</a></code> or
<code><a href="semantics.html#the-style-element">style</a></code> element. </p><p>A <code><a href="sections.html#the-body-element">body</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="sections.html#the-body-element">body</a></code> element is not
immediately followed by a <a href="#syntax-comments" title="syntax-comments">comment</a>.</p><p>A <code><a href="grouping-content.html#the-li-element">li</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="grouping-content.html#the-li-element">li</a></code> element is
immediately followed by another <code><a href="grouping-content.html#the-li-element">li</a></code> element or if there
is no more content in the parent element.</p><p>A <code><a href="grouping-content.html#the-dt-element">dt</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="grouping-content.html#the-dt-element">dt</a></code> element is
immediately followed by another <code><a href="grouping-content.html#the-dt-element">dt</a></code> element or a
<code><a href="grouping-content.html#the-dd-element">dd</a></code> element.</p><p>A <code><a href="grouping-content.html#the-dd-element">dd</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="grouping-content.html#the-dd-element">dd</a></code> element is
immediately followed by another <code><a href="grouping-content.html#the-dd-element">dd</a></code> element or a
<code><a href="grouping-content.html#the-dt-element">dt</a></code> element, or if there is no more content in the
parent element.</p><p>A <code><a href="grouping-content.html#the-p-element">p</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="grouping-content.html#the-p-element">p</a></code> element is
immediately followed by an <code><a href="sections.html#the-address-element">address</a></code>,
<code><a href="sections.html#the-article-element">article</a></code>, <code><a href="sections.html#the-aside-element">aside</a></code>, <code><a href="grouping-content.html#the-blockquote-element">blockquote</a></code>,
<code><a href="obsolete.html#dir">dir</a></code>, <code><a href="grouping-content.html#the-div-element">div</a></code>, <code><a href="grouping-content.html#the-dl-element">dl</a></code>,
<code><a href="forms.html#the-fieldset-element">fieldset</a></code>, <code><a href="sections.html#the-footer-element">footer</a></code>, <code><a href="forms.html#the-form-element">form</a></code>,
<code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h1</a></code>, <code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h2</a></code>, <code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h3</a></code>, <code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h4</a></code>,
<code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h5</a></code>, <code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h6</a></code>, <code><a href="sections.html#the-header-element">header</a></code>,
<code><a href="sections.html#the-hgroup-element">hgroup</a></code>, <code><a href="grouping-content.html#the-hr-element">hr</a></code>, <code><a href="interactive-elements.html#the-menu-element">menu</a></code>,
<code><a href="sections.html#the-nav-element">nav</a></code>, <code><a href="grouping-content.html#the-ol-element">ol</a></code>, <code><a href="grouping-content.html#the-p-element">p</a></code>, <code><a href="grouping-content.html#the-pre-element">pre</a></code>,
<code><a href="sections.html#the-section-element">section</a></code>, <code><a href="tabular-data.html#the-table-element">table</a></code>, or <code><a href="grouping-content.html#the-ul-element">ul</a></code>,
element, or if there is no more content in the parent element and
the parent element is not an <code><a href="text-level-semantics.html#the-a-element">a</a></code> element.</p><p>An <code><a href="text-level-semantics.html#the-rt-element">rt</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="text-level-semantics.html#the-rt-element">rt</a></code> element is
immediately followed by an <code><a href="text-level-semantics.html#the-rt-element">rt</a></code> or <code><a href="text-level-semantics.html#the-rp-element">rp</a></code>
element, or if there is no more content in the parent element.</p><p>An <code><a href="text-level-semantics.html#the-rp-element">rp</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="text-level-semantics.html#the-rp-element">rp</a></code> element is
immediately followed by an <code><a href="text-level-semantics.html#the-rt-element">rt</a></code> or <code><a href="text-level-semantics.html#the-rp-element">rp</a></code>
element, or if there is no more content in the parent element.</p><p>An <code><a href="the-button-element.html#the-optgroup-element">optgroup</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end tag</a> may be omitted if the
<code><a href="the-button-element.html#the-optgroup-element">optgroup</a></code> element is immediately followed by
another <code><a href="the-button-element.html#the-optgroup-element">optgroup</a></code> element, or if there is no
more content in the parent element.</p><p>An <code><a href="the-button-element.html#the-option-element">option</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="the-button-element.html#the-option-element">option</a></code> element is
immediately followed by another <code><a href="the-button-element.html#the-option-element">option</a></code> element, or if
it is immediately followed by an <code><a href="the-button-element.html#the-optgroup-element">optgroup</a></code> element, or
if there is no more content in the parent element.</p><p>A <code><a href="tabular-data.html#the-colgroup-element">colgroup</a></code> element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> may be omitted if the
first thing inside the <code><a href="tabular-data.html#the-colgroup-element">colgroup</a></code> element is a
<code><a href="tabular-data.html#the-col-element">col</a></code> element, and if the element is not immediately
preceded by another <code><a href="tabular-data.html#the-colgroup-element">colgroup</a></code> element whose <a href="#syntax-end-tag" title="syntax-end-tag">end tag</a> has been omitted. (It can't be
omitted if the element is empty.)</p><p>A <code><a href="tabular-data.html#the-colgroup-element">colgroup</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end tag</a> may be omitted if the
<code><a href="tabular-data.html#the-colgroup-element">colgroup</a></code> element is not immediately followed by a
<a href="common-microsyntaxes.html#space-character">space character</a> or a <a href="#syntax-comments" title="syntax-comments">comment</a>.</p><p>A <code><a href="tabular-data.html#the-thead-element">thead</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-thead-element">thead</a></code> element is
immediately followed by a <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> or <code><a href="tabular-data.html#the-tfoot-element">tfoot</a></code>
element.</p><p>A <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> element's <a href="#syntax-start-tag" title="syntax-start-tag">start tag</a> may be omitted if the
first thing inside the <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> element is a
<code><a href="tabular-data.html#the-tr-element">tr</a></code> element, and if the element is not immediately
preceded by a <code><a href="tabular-data.html#the-tbody-element">tbody</a></code>, <code><a href="tabular-data.html#the-thead-element">thead</a></code>, or
<code><a href="tabular-data.html#the-tfoot-element">tfoot</a></code> element whose <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> has been omitted. (It can't be omitted if the element is
empty.)</p><p>A <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> element is
immediately followed by a <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> or <code><a href="tabular-data.html#the-tfoot-element">tfoot</a></code>
element, or if there is no more content in the parent element.</p><p>A <code><a href="tabular-data.html#the-tfoot-element">tfoot</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-tfoot-element">tfoot</a></code> element is
immediately followed by a <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> element, or if there is
no more content in the parent element.</p><p>A <code><a href="tabular-data.html#the-tr-element">tr</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-tr-element">tr</a></code> element is
immediately followed by another <code><a href="tabular-data.html#the-tr-element">tr</a></code> element, or if there
is no more content in the parent element.</p><p>A <code><a href="tabular-data.html#the-td-element">td</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-td-element">td</a></code> element is
immediately followed by a <code><a href="tabular-data.html#the-td-element">td</a></code> or <code><a href="tabular-data.html#the-th-element">th</a></code>
element, or if there is no more content in the parent element.</p><p>A <code><a href="tabular-data.html#the-th-element">th</a></code> element's <a href="#syntax-end-tag" title="syntax-end-tag">end
tag</a> may be omitted if the <code><a href="tabular-data.html#the-th-element">th</a></code> element is
immediately followed by a <code><a href="tabular-data.html#the-td-element">td</a></code> or <code><a href="tabular-data.html#the-th-element">th</a></code>
element, or if there is no more content in the parent element.</p><p><strong>However</strong>, a <a href="#syntax-start-tag" title="syntax-start-tag">start
tag</a> must never be omitted if it has any attributes.</p><h5 id="element-restrictions"><span class="secno">8.1.2.5 </span>Restrictions on content models</h5><p>For historical reasons, certain elements have extra restrictions
beyond even the restrictions given by their content model.</p><p>A <code><a href="tabular-data.html#the-table-element">table</a></code> element must not contain <code><a href="tabular-data.html#the-tr-element">tr</a></code>
elements, even though these elements are technically allowed inside
<code><a href="tabular-data.html#the-table-element">table</a></code> elements according to the content models
described in this specification. (If a <code><a href="tabular-data.html#the-tr-element">tr</a></code> element is
put inside a <code><a href="tabular-data.html#the-table-element">table</a></code> in the markup, it will in fact imply
a <code><a href="tabular-data.html#the-tbody-element">tbody</a></code> start tag before it.)</p><p>A single <a href="#syntax-newlines" title="syntax-newlines">newline</a> may be
placed immediately after the <a href="#syntax-start-tag" title="syntax-start-tag">start
tag</a> of <code><a href="grouping-content.html#the-pre-element">pre</a></code> and <code><a href="the-button-element.html#the-textarea-element">textarea</a></code>
elements. This does not affect the processing of the element. The
otherwise optional <a href="#syntax-newlines" title="syntax-newlines">newline</a>
<em>must</em> be included if the element's contents themselves start
with a <a href="#syntax-newlines" title="syntax-newlines">newline</a> (because
otherwise the leading newline in the contents would be treated like
the optional newline, and ignored).</p><div class="example">
<p>The following two <code><a href="grouping-content.html#the-pre-element">pre</a></code> blocks are equivalent:</p>
<pre><pre>Hello</pre></pre>
<pre><pre><br>Hello</pre></pre>
</div><h5 id="cdata-rcdata-restrictions"><span class="secno">8.1.2.6 </span>Restrictions on the contents of raw text and RCDATA elements</h5><p>The text in <a href="#raw-text-elements" title="raw text elements">raw text</a> and
<a href="#rcdata-elements">RCDATA elements</a> must not contain any occurrences of the
string "<code title=""></</code>" (U+003C LESS-THAN SIGN, U+002F
SOLIDUS) followed by characters that case-insensitively match the
tag name of the element followed by one of U+0009 CHARACTER
TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), U+000D
CARRIAGE RETURN (CR), U+0020 SPACE, U+003E GREATER-THAN SIGN (>), or
U+002F SOLIDUS (/).</p><h4 id="text-0"><span class="secno">8.1.3 </span>Text</h4><p><dfn id="syntax-text" title="syntax-text">Text</dfn> is allowed inside elements,
attribute values, and comments. Text must consist of Unicode
characters. Text must not contain U+0000 characters. Text must not
contain permanently undefined Unicode characters (noncharacters).
Text must not contain control characters other than <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>. Extra constraints
are placed on what is and what is not allowed in text based on where
the text is to be put, as described in the other sections.</p><h5 id="newlines"><span class="secno">8.1.3.1 </span>Newlines</h5><p><dfn id="syntax-newlines" title="syntax-newlines">Newlines</dfn> in HTML may be
represented either as U+000D CARRIAGE RETURN (CR) characters, U+000A
LINE FEED (LF) characters, or pairs of U+000D CARRIAGE RETURN (CR),
U+000A LINE FEED (LF) characters in that order.</p><p>Where <a href="#syntax-charref" title="syntax-charref">character references</a>
are allowed, a character reference of a U+000A LINE FEED (LF)
character (but not a U+000D CARRIAGE RETURN (CR) character) also
represents a <a href="#syntax-newlines" title="syntax-newlines">newline</a>.</p><h4 id="character-references"><span class="secno">8.1.4 </span>Character references</h4><p>In certain cases described in other sections, <a href="#syntax-text" title="syntax-text">text</a> may be mixed with <dfn id="syntax-charref" title="syntax-charref">character references</dfn>. These can be used
to escape characters that couldn't otherwise legally be included in
<a href="#syntax-text" title="syntax-text">text</a>.</p><p>Character references must start with a U+0026 AMPERSAND character
(&). Following this, there are three possible kinds of character
references:</p><dl><dt>Named character references</dt>
<dd>The ampersand must be followed by one of the names given in the
<a href="named-character-references.html#named-character-references">named character references</a> section, using the same
case. <span class="impl">The name must be one that is terminated by
a U+003B SEMICOLON character (;).</span></dd>
<dt>Decimal numeric character reference</dt>
<dd>The ampersand must be followed by a U+0023 NUMBER SIGN
character (#), followed by one or more digits in the range U+0030
DIGIT ZERO (0) to U+0039 DIGIT NINE (9), representing a base-ten
integer that corresponds to a Unicode code point that is allowed
according to the definition below. The digits must then be followed
by a U+003B SEMICOLON character (;).</dd>
<dt>Hexadecimal numeric character reference</dt>
<dd>The ampersand must be followed by a U+0023 NUMBER SIGN
character (#), which must be followed by either a U+0078 LATIN
SMALL LETTER X character (x) or a U+0058 LATIN CAPITAL LETTER X
character (X), which must then be followed by one or more digits in
the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0061
LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F, and U+0041
LATIN CAPITAL LETTER A to U+0046 LATIN CAPITAL LETTER F,
representing a base-sixteen integer that corresponds to a Unicode
code point that is allowed according to the definition below. The
digits must then be followed by a U+003B SEMICOLON character
(;).</dd>
</dl><p>The numeric character reference forms described above are allowed
to reference any Unicode code point other than U+0000, U+000D,
permanently undefined Unicode characters (noncharacters), and
control characters other than <a href="common-microsyntaxes.html#space-character" title="space character">space
characters</a>.</p><p>An <dfn id="syntax-ambiguous-ampersand" title="syntax-ambiguous-ampersand">ambiguous
ampersand</dfn> is a U+0026 AMPERSAND character (&) that is
followed by one or more characters in the range U+0030 DIGIT ZERO
(0) to U+0039 DIGIT NINE (9), U+0061 LATIN SMALL LETTER A to U+007A
LATIN SMALL LETTER Z, and U+0041 LATIN CAPITAL LETTER A to U+005A
LATIN CAPITAL LETTER Z, followed by a U+003B SEMICOLON character
(;), where these characters do not match any of the names given in
the <a href="named-character-references.html#named-character-references">named character references</a> section.</p><h4 id="cdata-sections"><span class="secno">8.1.5 </span>CDATA sections</h4><p><dfn id="syntax-cdata" title="syntax-cdata">CDATA sections</dfn> must consist of
the following components, in this order:</p><ol><li>The string "<code title=""><![CDATA[</code>".</li>
<li>Optionally, <a href="#syntax-text" title="syntax-text">text</a>, with the
additional restriction that the text must not contain the string
"<code title="">]]></code>".</li>
<li>The string "<code title="">]]></code>".</li>
</ol><div class="example">
<p>CDATA sections can only be used in foreign content (MathML or
SVG). In this example, a CDATA section is used to escape the
contents of an <code>ms</code> element:</p>
<pre><p>You can add a string to a number, but this stringifies the number:</p>
<math>
<ms><![CDATA[x<y]]></ms>
<mo>+</mo>
<mn>3</mn>
<mo>=</mo>
<ms><![CDATA[x<y3]]></ms>
</math></pre>
</div><h4 id="comments"><span class="secno">8.1.6 </span>Comments</h4><p><dfn id="syntax-comments" title="syntax-comments">Comments</dfn> must start with the
four character sequence U+003C LESS-THAN SIGN, U+0021 EXCLAMATION
MARK, U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS (<code title=""><!--</code>). Following this sequence, the comment may
have <a href="#syntax-text" title="syntax-text">text</a>, with the additional
restriction that the text must not start with a single U+003E
GREATER-THAN SIGN character (>), nor start with a U+002D
HYPHEN-MINUS character (-) followed by a U+003E GREATER-THAN SIGN
(>) character, nor contain two consecutive U+002D HYPHEN-MINUS
characters (<code title="">--</code>), nor end with a U+002D
HYPHEN-MINUS character (-). Finally, the comment must be ended by
the three character sequence U+002D HYPHEN-MINUS, U+002D
HYPHEN-MINUS, U+003E GREATER-THAN SIGN (<code title="">--></code>).</p></body></html>