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998 lines
72 KiB
998 lines
72 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html lang="en-US-x-Hixie" ><head><title>8 The HTML syntax — HTML5 </title><style type="text/css">
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pre { margin-left: 2em; white-space: pre-wrap; }
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h2 { margin: 3em 0 1em 0; }
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h3 { margin: 2.5em 0 1em 0; }
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h4 { margin: 2.5em 0 0.75em 0; }
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h5, h6 { margin: 2.5em 0 1em; }
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h1 + h2, h1 + h2 + h2 { margin: 0.75em 0 0.75em; }
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h2 + h3, h3 + h4, h4 + h5, h5 + h6 { margin-top: 0.5em; }
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p { margin: 1em 0; }
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hr:not(.top) { display: block; background: none; border: none; padding: 0; margin: 2em 0; height: auto; }
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dl, dd { margin-top: 0; margin-bottom: 0; }
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dt { margin-top: 0.75em; margin-bottom: 0.25em; clear: left; }
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dt + dt { margin-top: 0; }
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dd dt { margin-top: 0.25em; margin-bottom: 0; }
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dd p { margin-top: 0; }
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dd dl + p { margin-top: 1em; }
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dd table + p { margin-top: 1em; }
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p + * > li, dd li { margin: 1em 0; }
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dt, dfn { font-weight: bold; font-style: normal; }
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dt dfn { font-style: italic; }
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pre, code { font-size: inherit; font-family: monospace; font-variant: normal; }
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pre strong { color: black; font: inherit; font-weight: bold; background: yellow; }
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pre em { font-weight: bolder; font-style: normal; }
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@media screen { code { color: orangered; } code :link, code :visited { color: inherit; } }
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var sub { vertical-align: bottom; font-size: smaller; position: relative; top: 0.1em; }
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table { border-collapse: collapse; border-style: hidden hidden none hidden; }
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table thead, table tbody { border-bottom: solid; }
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table tbody th:first-child { border-left: solid; }
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table tbody th { text-align: left; }
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table td, table th { border-left: solid; border-right: solid; border-bottom: solid thin; vertical-align: top; padding: 0.2em; }
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blockquote { margin: 0 0 0 2em; border: 0; padding: 0; font-style: italic; }
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.bad, .bad *:not(.XXX) { color: gray; border-color: gray; background: transparent; }
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.matrix, .matrix td { border: none; text-align: right; }
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.matrix { margin-left: 2em; }
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.dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
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.dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
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.dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
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.toc dfn, h1 dfn, h2 dfn, h3 dfn, h4 dfn, h5 dfn, h6 dfn { font: inherit; }
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img.extra { float: right; }
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pre.idl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; }
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pre.idl :link, pre.idl :visited { color: inherit; background: transparent; }
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pre.css { border: solid thin; background: #FFFFEE; color: black; padding: 0.5em 1em; }
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pre.css:first-line { color: #AAAA50; }
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dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
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hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
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dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
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dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
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dl.domintro dd p { margin: 0.5em 0; }
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dl.switch { padding-left: 2em; }
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dl.switch > dt { text-indent: -1.5em; }
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dl.switch > dt:before { content: '\21AA'; padding: 0 0.5em 0 0; display: inline-block; width: 1em; text-align: right; line-height: 0.5em; }
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dl.triple { padding: 0 0 0 1em; }
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dl.triple dt, dl.triple dd { margin: 0; display: inline }
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dl.triple dt:after { content: ':'; }
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dl.triple dd:after { content: '\A'; white-space: pre; }
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.diff-old { text-decoration: line-through; color: silver; background: transparent; }
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.diff-chg, .diff-new { text-decoration: underline; color: green; background: transparent; }
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a .diff-new { border-bottom: 1px blue solid; }
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h2 { page-break-before: always; }
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h1, h2, h3, h4, h5, h6 { page-break-after: avoid; }
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h1 + h2, hr + h2.no-toc { page-break-before: auto; }
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p > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]),
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li > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]), { border-bottom: solid #9999CC; }
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div.head { margin: 0 0 1em; padding: 1em 0 0 0; }
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div.head p { margin: 0; }
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div.head h1 { margin: 0; }
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div.head .logo { float: right; margin: 0 1em; }
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div.head .logo img { border: none } /* remove border from top image */
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div.head dl { margin: 1em 0; }
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div.head p.copyright, div.head p.alt { font-size: x-small; font-style: oblique; margin: 0; }
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body > .toc > li { margin-top: 1em; margin-bottom: 1em; }
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body > .toc.brief > li { margin-top: 0.35em; margin-bottom: 0.35em; }
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body > .toc > li > * { margin-bottom: 0.5em; }
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body > .toc > li > * > li > * { margin-bottom: 0.25em; }
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.toc, .toc li { list-style: none; }
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.brief { margin-top: 1em; margin-bottom: 1em; line-height: 1.1; }
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.brief li { margin: 0; padding: 0; }
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.brief li p { margin: 0; padding: 0; }
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.category-list { margin-top: -0.75em; margin-bottom: 1em; line-height: 1.5; }
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.category-list::before { content: '\21D2\A0'; font-size: 1.2em; font-weight: 900; }
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.category-list li { display: inline; }
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.category-list li:not(:last-child)::after { content: ', '; }
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.category-list li > span, .category-list li > a { text-transform: lowercase; }
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.category-list li * { text-transform: none; } /* don't affect <code> nested in <a> */
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.XXX { color: #E50000; background: white; border: solid red; padding: 0.5em; margin: 1em 0; }
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.XXX > :first-child { margin-top: 0; }
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p .XXX { line-height: 3em; }
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.annotation { border: solid thin black; background: #0C479D; color: white; position: relative; margin: 8px 0 20px 0; }
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.annotation:before { position: absolute; left: 0; top: 0; width: 100%; height: 100%; margin: 6px -6px -6px 6px; background: #333333; z-index: -1; content: ''; }
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.annotation :link, .annotation :visited { color: inherit; }
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.annotation :link:hover, .annotation :visited:hover { background: transparent; }
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.annotation span { border: none ! important; }
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.note { color: green; background: transparent; font-family: sans-serif; }
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.warning { color: red; background: transparent; }
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.note, .warning { font-weight: bolder; font-style: italic; }
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p.note, div.note { padding: 0.5em 2em; }
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span.note { padding: 0 2em; }
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.note p:first-child, .warning p:first-child { margin-top: 0; }
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.note p:last-child, .warning p:last-child { margin-bottom: 0; }
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.warning:before { font-style: normal; }
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p.note:before { content: 'Note: '; }
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p.warning:before { content: '\26A0 Warning! '; }
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.bookkeeping:before { display: block; content: 'Bookkeeping details'; font-weight: bolder; font-style: italic; }
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.bookkeeping { font-size: 0.8em; margin: 2em 0; }
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.bookkeeping p { margin: 0.5em 2em; display: list-item; list-style: square; }
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.bookkeeping dt { margin: 0.5em 2em 0; }
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.bookkeeping dd { margin: 0 3em 0.5em; }
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h4 { position: relative; z-index: 3; }
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h4 + .element, h4 + div + .element { margin-top: -2.5em; padding-top: 2em; }
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.element {
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background: #EEEEFF;
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color: black;
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margin: 0 0 1em 0.15em;
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padding: 0 1em 0.25em 0.75em;
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border-left: solid #9999FF 0.25em;
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position: relative;
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z-index: 1;
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}
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.element:before {
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position: absolute;
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z-index: 2;
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top: 0;
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left: -1.15em;
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height: 2em;
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width: 0.9em;
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background: #EEEEFF;
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content: ' ';
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border-style: none none solid solid;
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border-color: #9999FF;
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border-width: 0.25em;
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}
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.example { display: block; color: #222222; background: #FCFCFC; border-left: double; margin-left: 2em; padding-left: 1em; }
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td > .example:only-child { margin: 0 0 0 0.1em; }
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ul.domTree, ul.domTree ul { padding: 0 0 0 1em; margin: 0; }
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ul.domTree li { padding: 0; margin: 0; list-style: none; position: relative; }
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ul.domTree li li { list-style: none; }
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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; }
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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; }
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ul.domTree span { font-style: italic; font-family: serif; }
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ul.domTree .t1 code { color: purple; font-weight: bold; }
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ul.domTree .t2 { font-style: normal; font-family: monospace; }
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ul.domTree .t2 .name { color: black; font-weight: bold; }
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ul.domTree .t2 .value { color: blue; font-weight: normal; }
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ul.domTree .t3 code, .domTree .t4 code, .domTree .t5 code { color: gray; }
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ul.domTree .t7 code, .domTree .t8 code { color: green; }
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ul.domTree .t10 code { color: teal; }
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body.dfnEnabled dfn { cursor: pointer; }
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.dfnPanel {
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display: inline;
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position: absolute;
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z-index: 10;
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height: auto;
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width: auto;
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padding: 0.5em 0.75em;
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font: small sans-serif, Droid Sans Fallback;
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background: #DDDDDD;
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color: black;
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border: outset 0.2em;
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}
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.dfnPanel * { margin: 0; padding: 0; font: inherit; text-indent: 0; }
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.dfnPanel :link, .dfnPanel :visited { color: black; }
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.dfnPanel p { font-weight: bolder; }
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.dfnPanel * + p { margin-top: 0.25em; }
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.dfnPanel li { list-style-position: inside; }
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#configUI { position: absolute; z-index: 20; top: 10em; right: 1em; width: 11em; font-size: small; }
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#configUI p { margin: 0.5em 0; padding: 0.3em; background: #EEEEEE; color: black; border: inset thin; }
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#configUI p label { display: block; }
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#configUI #updateUI, #configUI .loginUI { text-align: center; }
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#configUI input[type=button] { display: block; margin: auto; }
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fieldset { margin: 1em; padding: 0.5em 1em; }
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fieldset > legend + * { margin-top: 0; }
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fieldset > :last-child { margin-bottom: 0; }
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fieldset p { margin: 0.5em 0; }
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.stability {
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position: fixed;
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bottom: 0;
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left: 0; right: 0;
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margin: 0 auto 0 auto !important;
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z-index: 1000;
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width: 50%;
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background: maroon; color: yellow;
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-webkit-border-radius: 1em 1em 0 0;
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-moz-border-radius: 1em 1em 0 0;
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border-radius: 1em 1em 0 0;
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-moz-box-shadow: 0 0 1em #500;
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-webkit-box-shadow: 0 0 1em #500;
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box-shadow: 0 0 1em red;
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padding: 0.5em 1em;
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text-align: center;
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}
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.stability strong {
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display: block;
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}
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.stability input {
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appearance: none; margin: 0; border: 0; padding: 0.25em 0.5em; background: transparent; color: black;
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position: absolute; top: -0.5em; right: 0; font: 1.25em sans-serif; text-align: center;
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}
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.stability input:hover {
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color: white;
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text-shadow: 0 0 2px black;
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}
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.stability input:active {
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padding: 0.3em 0.45em 0.2em 0.55em;
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}
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.stability :link, .stability :visited,
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.stability :link:hover, .stability :visited:hover {
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background: transparent;
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color: white;
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}
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</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
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requirements"><link href="http://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css"><style type="text/css">
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.applies thead th > * { display: block; }
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.applies thead code { display: block; }
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.applies tbody th { whitespace: nowrap; }
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.applies td { text-align: center; }
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.applies .yes { background: yellow; }
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.matrix, .matrix td { border: hidden; text-align: right; }
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.matrix { margin-left: 2em; }
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.dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
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.dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
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.dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
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td.eg { border-width: thin; text-align: center; }
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#table-example-1 { border: solid thin; border-collapse: collapse; margin-left: 3em; }
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#table-example-1 * { font-family: "Essays1743", serif; line-height: 1.01em; }
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#table-example-1 caption { padding-bottom: 0.5em; }
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#table-example-1 thead, #table-example-1 tbody { border: none; }
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#table-example-1 th, #table-example-1 td { border: solid thin; }
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#table-example-1 th { font-weight: normal; }
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#table-example-1 td { border-style: none solid; vertical-align: top; }
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#table-example-1 th { padding: 0.5em; vertical-align: middle; text-align: center; }
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#table-example-1 tbody tr:first-child td { padding-top: 0.5em; }
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#table-example-1 tbody tr:last-child td { padding-bottom: 1.5em; }
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#table-example-1 tbody td:first-child { padding-left: 2.5em; padding-right: 0; width: 9em; }
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#table-example-1 tbody td:first-child::after { content: leader(". "); }
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#table-example-1 tbody td { padding-left: 2em; padding-right: 2em; }
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#table-example-1 tbody td:first-child + td { width: 10em; }
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#table-example-1 tbody td:first-child + td ~ td { width: 2.5em; }
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#table-example-1 tbody td:first-child + td + td + td ~ td { width: 1.25em; }
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.apple-table-examples { border: none; border-collapse: separate; border-spacing: 1.5em 0em; width: 40em; margin-left: 3em; }
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.apple-table-examples * { font-family: "Times", serif; }
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.apple-table-examples td, .apple-table-examples th { border: none; white-space: nowrap; padding-top: 0; padding-bottom: 0; }
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.apple-table-examples tbody th:first-child { border-left: none; width: 100%; }
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.apple-table-examples thead th:first-child ~ th { font-size: smaller; font-weight: bolder; border-bottom: solid 2px; text-align: center; }
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.apple-table-examples tbody th::after, .apple-table-examples tfoot th::after { content: leader(". ") }
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.apple-table-examples tbody th, .apple-table-examples tfoot th { font: inherit; text-align: left; }
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.apple-table-examples td { text-align: right; vertical-align: top; }
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.apple-table-examples.e1 tbody tr:last-child td { border-bottom: solid 1px; }
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.apple-table-examples.e1 tbody + tbody tr:last-child td { border-bottom: double 3px; }
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.apple-table-examples.e2 th[scope=row] { padding-left: 1em; }
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.apple-table-examples sup { line-height: 0; }
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.details-example img { vertical-align: top; }
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#base64-table {
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white-space: nowrap;
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font-size: 0.6em;
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column-width: 6em;
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column-count: 5;
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column-gap: 1em;
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-moz-column-width: 6em;
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-moz-column-count: 5;
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-moz-column-gap: 1em;
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-webkit-column-width: 6em;
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-webkit-column-count: 5;
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-webkit-column-gap: 1em;
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}
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#base64-table thead { display: none; }
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#base64-table * { border: none; }
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#base64-table tbody td:first-child:after { content: ':'; }
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#base64-table tbody td:last-child { text-align: right; }
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#named-character-references-table {
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white-space: nowrap;
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font-size: 0.6em;
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column-width: 30em;
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column-gap: 1em;
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-moz-column-width: 30em;
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-moz-column-gap: 1em;
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-webkit-column-width: 30em;
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-webkit-column-gap: 1em;
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}
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#named-character-references-table > table > tbody > tr > td:first-child + td,
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#named-character-references-table > table > tbody > tr > td:last-child { text-align: center; }
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#named-character-references-table > table > tbody > tr > td:last-child:hover > span { position: absolute; top: auto; left: auto; margin-left: 0.5em; line-height: 1.2; font-size: 5em; border: outset; padding: 0.25em 0.5em; background: white; width: 1.25em; height: auto; text-align: center; }
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#named-character-references-table > table > tbody > tr#entity-CounterClockwiseContourIntegral > td:first-child { font-size: 0.5em; }
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.glyph.control { color: red; }
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@font-face {
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font-family: 'Essays1743';
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src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743.ttf');
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}
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@font-face {
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font-family: 'Essays1743';
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font-weight: bold;
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src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Bold.ttf');
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}
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@font-face {
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font-family: 'Essays1743';
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font-style: italic;
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src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Italic.ttf');
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}
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@font-face {
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font-family: 'Essays1743';
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font-style: italic;
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font-weight: bold;
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src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-BoldItalic.ttf');
|
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}
|
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|
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</style><style type="text/css">
|
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.domintro:before { display: table; margin: -1em -0.5em -0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: black; font-style: italic; border: solid 2px; background: white; padding: 0 0.25em; }
|
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</style><script type="text/javascript">
|
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function getCookie(name) {
|
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var params = location.search.substr(1).split("&");
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for (var index = 0; index < params.length; index++) {
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if (params[index] == name)
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return "1";
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var data = params[index].split("=");
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if (data[0] == name)
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return unescape(data[1]);
|
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}
|
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var cookies = document.cookie.split("; ");
|
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for (var index = 0; index < cookies.length; index++) {
|
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var data = cookies[index].split("=");
|
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if (data[0] == name)
|
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return unescape(data[1]);
|
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}
|
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return null;
|
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}
|
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</script>
|
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<script src="link-fixup.js" type="text/javascript"></script>
|
|
<link href="style.css" rel="stylesheet"><link href="dnd.html" title="7.7 Drag and drop" rel="prev">
|
|
<link href="spec.html#contents" title="Table of contents" rel="index">
|
|
<link href="parsing.html" title="8.2 Parsing HTML documents" rel="next">
|
|
</head><body><div class="head" id="head">
|
|
<div id="multipage-common">
|
|
<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>
|
|
with changes based on resolution of Last Call issues.
|
|
<input onclick="closeWarning(this.parentNode)" type="button" value="╳⃝"></p>
|
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<script type="text/javascript">
|
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function closeWarning(element) {
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element.parentNode.removeChild(element);
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var date = new Date();
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date.setDate(date.getDate()+4);
|
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document.cookie = 'hide-obsolescence-warning=1; expires=' + date.toGMTString();
|
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}
|
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if (getCookie('hide-obsolescence-warning') == '1')
|
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setTimeout(function () { document.getElementById('wip').parentNode.removeChild(document.getElementById('wip')); }, 2000);
|
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</script></div>
|
|
|
|
<p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>
|
|
|
|
<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>
|