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<!DOCTYPE html><html lang=en><head>
<meta content="text/html; charset=utf-8" http-equiv=Content-Type>
<title>Non-element Selectors</title>
<link href=../default.css rel=stylesheet type=text/css>
<link href=../csslogo.ico rel="shortcut icon" type=image/x-icon>
<style>
body {
background: url("https://www.w3.org/StyleSheets/TR/logo-ED") top left no-repeat white;
background-attachment: fixed;
color: black;
font-family: sans-serif;
margin: 0 auto;
max-width: 50em;
padding: 2em 1em 2em 70px;
}
:link { color: #00C; background: transparent }
:visited { color: #609; background: transparent }
a[href]:active { color: #C00; background: transparent }
a[href]:hover { background: #ffa }
a[href] img { border-style: none }
h1, h2, h3, h4, h5, h6 { text-align: left }
h1, h2, h3 { color: #005A9C; }
h1 { font: 170% sans-serif }
h2 { font: 140% sans-serif }
h3 { font: 120% sans-serif }
h4 { font: bold 100% sans-serif }
h5 { font: italic 100% sans-serif }
h6 { font: small-caps 100% sans-serif }
.hide { display: none }
div.head { margin-bottom: 1em }
div.head h1 { margin-top: 2em; clear: both }
div.head table { margin-left: 2em; margin-top: 2em }
p.copyright { font-size: small }
p.copyright small { font-size: small }
pre { margin-left: 2em }
dt { font-weight: bold }
ul.toc, ol.toc {
list-style: none;
}
</style>
</head>
<body class=h-entry>
<div class=head>
<p data-fill-with=logo><a class=logo href=http://www.w3.org/>
<img alt=W3C height=48 src=http://www.w3.org/Icons/w3c_home width=72>
</a>
</p>
<h1 class="p-name no-ref" id=title>Non-element Selectors</h1>
<h2 class="no-num no-toc no-ref heading settled heading" id=subtitle><span class=content>Editor’s Draft,
<span class=dt-updated><span class=value-title title=20140215>15 February 2014</span></span></span></h2>
<div data-fill-with=spec-metadata><dl><dt>This version:<dd><a class=u-url href=http://dev.w3.org/csswg/selectors-nonelement/>http://dev.w3.org/csswg/selectors-nonelement/</a><dt>Editor’s Draft:<dd><a href=http://dev.w3.org/csswg/selectors-nonelement/>http://dev.w3.org/csswg/selectors-nonelement/</a>
<dt>Feedback:</dt>
<dd><a href="mailto:www-style@w3.org?subject=%5Bselectors-nonelement%5D%20feedback">www-style@w3.org</a>
with subject line
“<kbd>[selectors-nonelement] <var>… message topic …</var></kbd>”(<a href=http://lists.w3.org/Archives/Public/www-style/ rel=discussion>archives</a>)<dt>Test Suite:<dd>None Yet<dt>Editors:
<dd class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:jirka@kosek.cz>Jirka Kosek</a> (<span class="p-org org">Invited Expert</span>)<dd class="p-author h-card vcard"><a class="p-name fn u-url url" href=http://xanthir.com/contact/>Tab Atkins Jr.</a> (<span class="p-org org">Google</span>)</dl></div>
<div data-fill-with=warning></div>
<p class=copyright data-fill-with=copyright><a href=http://www.w3.org/Consortium/Legal/ipr-notice#Copyright>Copyright</a> © 2014 <a href=http://www.w3.org/><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href=http://www.csail.mit.edu/><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href=http://www.ercim.eu/><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href=http://www.keio.ac.jp/>Keio</a>, <a href=http://ev.buaa.edu.cn/>Beihang</a>), All Rights Reserved. W3C <a href=http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer>liability</a>, <a href=http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks>trademark</a> and <a href=http://www.w3.org/Consortium/Legal/copyright-documents>document use</a> rules apply.
</p>
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc no-ref heading settled heading" id=abstract><span class=content>Abstract</span></h2>
<p class=p-summary data-fill-with=abstract>Non-element Selectors extends <a data-biblio-type=normative data-link-type=biblio href=#selectors4 title=selectors4>[SELECTORS4]</a> and allow selecting other kinds of document nodes then elements. This is useful when selectors are used as a general document query language.<p>Non-element Selectors are not intended to be used in CSS, but only as a separate query language in other host environments.
<a href=http://www.w3.org/TR/CSS/>CSS</a> is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, in speech, etc.</p>
<h2 class="no-num no-toc no-ref heading settled heading" id=status><span class=content>Status of this document</span></h2>
<div data-fill-with=status><p>
This is a public copy of the editors’ draft.
It is provided for discussion only and may change at any moment.
Its publication here does not imply endorsement of its contents by W3C.
Don’t cite this document other than as work in progress.
<p>
The (<a href=http://lists.w3.org/Archives/Public/www-style/>archived</a>) public mailing list
<a href="mailto:www-style@w3.org?Subject=%5Bselectors-nonelement%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>
(see <a href=http://www.w3.org/Mail/Request>instructions</a>)
is preferred for discussion of this specification.
When sending e-mail,
please put the text “selectors-nonelement” in the subject,
preferably like this:
“[selectors-nonelement] <em>…summary of comment…</em>”
<p>
This document was produced by the <a href=http://www.w3.org/Style/CSS/members>CSS Working Group</a>
(part of the <a href=http://www.w3.org/Style/>Style Activity</a>).
<p>
This document was produced by a group operating under
the <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/>5 February 2004 W3C Patent Policy</a>.
W3C maintains a <a href=http://www.w3.org/2004/01/pp-impl/32061/status rel=disclosure>public list of any patent disclosures</a>
made in connection with the deliverables of the group;
that page also includes instructions for disclosing a patent.
An individual who has actual knowledge of a patent which the individual believes contains <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential>Essential Claim(s)</a>
must disclose the information in accordance with <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure>section 6 of the W3C Patent Policy</a>.</div>
<div data-fill-with=at-risk></div>
<h2 class="no-num no-toc no-ref heading settled heading" id=contents><span class=content>Table of Contents</span></h2>
<div data-fill-with=table-of-contents><ul class=toc>
<li><a href=#intro><span class=secno>1</span> Introduction</a>
<li><a href=#non-element-selectors><span class=secno>2</span> Non-element Selectors</a>
<ul class=toc>
<li><a href=#attribute-node-selector><span class=secno>2.1</span> Attribute node selector</a></ul>
<li><a href=#conformance><span class=secno></span> Conformance</a>
<ul class=toc>
<li><a href=#conventions><span class=secno></span> Document conventions</a>
<li><a href=#conformance-classes><span class=secno></span> Conformance classes</a>
<li><a href=#partial><span class=secno></span> Partial implementations</a>
<li><a href=#experimental><span class=secno></span> Experimental implementations</a>
<li><a href=#testing><span class=secno></span> Non-experimental implementations</a></ul>
<li><a href=#references><span class=secno></span> References</a>
<ul class=toc>
<li><a href=#normative><span class=secno></span> Normative References</a>
<li><a href=#informative><span class=secno></span> Informative References</a></ul>
<li><a href=#index><span class=secno></span> Index</a>
<li><a href=#property-index><span class=secno></span> Property index</a></ul></div>
<h2 class="heading settled heading" data-level=1 id=intro><span class=secno>1 </span><span class=content>
Introduction</span><a class=self-link href=#intro></a></h2>
<p> Selectors are a very popular mechanism for selecting things in HTML and XML content.
They are not used only in CSS <a data-biblio-type=informative data-link-type=biblio href=#css3syn title=css3syn>[CSS3SYN]</a>
but also as a standalone query language in libraries like <a href=http://jquery.com/>jQuery</a>,
in newer standardized browser APIs like <a data-biblio-type=informative data-link-type=biblio href=#selectors-api title=selectors-api>[SELECTORS-API]</a>
and in other Web standards like <a href=http://www.w3.org/TR/its20/>ITS 2.0</a>.
<p> The <a data-biblio-type=informative data-link-type=biblio href=#selectors4 title=selectors4>[SELECTORS4]</a> specification only defines selectors for selecting element nodes from the document,
but some uses of Selectors would like to select other types of nodes as well.
This specification extends <a data-biblio-type=informative data-link-type=biblio href=#selectors4 title=selectors4>[SELECTORS4]</a> with additional selectors
that can be used for selecting non-element nodes in a document tree.
<p class=note> Note: Currently the draft only defines means for selecting and matching attribute nodes,
but other kinds of nodes, such as comments or processing instructions, might be supported in the future.
<h2 class="heading settled heading" data-level=2 id=non-element-selectors><span class=secno>2 </span><span class=content>
Non-element Selectors</span><a class=self-link href=#non-element-selectors></a></h2>
<h3 class="heading settled heading" data-level=2.1 id=attribute-node-selector><span class=secno>2.1 </span><span class=content>
Attribute node selector</span><a class=self-link href=#attribute-node-selector></a></h3>
<p> An <dfn data-dfn-type=dfn data-export="" id=attribute-node-pseudo-element>attribute node pseudo-element<a class=self-link href=#attribute-node-pseudo-element></a></dfn> represents an attribute node in a document tree.
Its syntax is:
<pre class=prod><dfn class=css-code data-dfn-type=selector data-export="" id=selectordef-attr>::attr()<a class=self-link href=#selectordef-attr></a></dfn> = ::attr( <a class="production css-code" data-link-type=type href=#typedef-qualified-name title="<qualified-name>"><qualified-name></a> )</pre>
<p> Where <dfn class=css-code data-dfn-type=type data-export="" id=typedef-qualified-name><qualified-name><a class=self-link href=#typedef-qualified-name></a></dfn> is a <a data-link-spec=css-namespaces data-link-type=dfn href=http://dev.w3.org/csswg/css-namespaces-1/#css-qualified-name title="css qualified name">CSS qualified name</a>.
<p> The pseudo-element matches an attribute node with the given qualified name,
if such an attribute exists on the <a data-link-spec=selectors data-link-type=dfn href=http://dev.w3.org/csswg/selectors-4/#originating-element title="originating element">originating element</a>.
<div class=example>
The following ITS rules use an attribute node selector to switch off translatability of <code>title</code> attributes on <code>abbr</code> elements.
<pre> <rules xmlns="http://www.w3.org/2005/11/its"
version="2.0"
queryLanguage="css">
<translateRule selector="abbr::attr(title)" translate="no"/>
</rules>
</pre>
</div>
<p> Although entirely valid in Selectors used in the scope of CSS,
attribute node pseudo-elements never generate boxes.
<h2 class="no-ref no-num heading settled heading" id=conformance><span class=content>
Conformance</span><a class=self-link href=#conformance></a></h2>
<h3 class="no-ref heading settled heading" id=conventions><span class=content>
Document conventions</span><a class=self-link href=#conventions></a></h3>
<p>Conformance requirements are expressed with a combination of
descriptive assertions and RFC 2119 terminology. The key words "MUST",
"MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this
document are to be interpreted as described in RFC 2119.
However, for readability, these words do not appear in all uppercase
letters in this specification.
<p>All of the text of this specification is normative except sections
explicitly marked as non-normative, examples, and notes. <a data-biblio-type=normative data-link-type=biblio href=#rfc2119 title=rfc2119>[RFC2119]</a></p>
<p>Examples in this specification are introduced with the words "for example"
or are set apart from the normative text with <code>class="example"</code>,
like this:
<div class=example>
<p>This is an example of an informative example.</p>
</div>
<p>Informative notes begin with the word "Note" and are set apart from the
normative text with <code>class="note"</code>, like this:
<p class=note>Note, this is an informative note.</p>
<h3 class="no-ref heading settled heading" id=conformance-classes><span class=content>
Conformance classes</span><a class=self-link href=#conformance-classes></a></h3>
<p>Conformance to this specification
is defined for three conformance classes:
<dl>
<dt>style sheet
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#style-sheet>CSS
style sheet</a>.
<dt>renderer
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#user-agent>UA</a>
that interprets the semantics of a style sheet and renders
documents that use them.
<dt>authoring tool
<dd>A <a href=http://www.w3.org/TR/CSS21/conform.html#user-agent>UA</a>
that writes a style sheet.
</dl>
<p>A style sheet is conformant to this specification
if all of its statements that use syntax defined in this module are valid
according to the generic CSS grammar and the individual grammars of each
feature defined in this module.
<p>A renderer is conformant to this specification
if, in addition to interpreting the style sheet as defined by the
appropriate specifications, it supports all the features defined
by this specification by parsing them correctly
and rendering the document accordingly. However, the inability of a
UA to correctly render a document due to limitations of the device
does not make the UA non-conformant. (For example, a UA is not
required to render color on a monochrome monitor.)
<p>An authoring tool is conformant to this specification
if it writes style sheets that are syntactically correct according to the
generic CSS grammar and the individual grammars of each feature in
this module, and meet all other conformance requirements of style sheets
as described in this module.
<h3 class="no-ref heading settled heading" id=partial><span class=content>
Partial implementations</span><a class=self-link href=#partial></a></h3>
<p>So that authors can exploit the forward-compatible parsing rules to
assign fallback values, CSS renderers <strong>must</strong>
treat as invalid (and <a href=http://www.w3.org/TR/CSS21/conform.html#ignore>ignore
as appropriate</a>) any at-rules, properties, property values, keywords,
and other syntactic constructs for which they have no usable level of
support. In particular, user agents <strong>must not</strong> selectively
ignore unsupported component values and honor supported values in a single
multi-value property declaration: if any value is considered invalid
(as unsupported values must be), CSS requires that the entire declaration
be ignored.</p>
<h3 class="no-ref heading settled heading" id=experimental><span class=content>
Experimental implementations</span><a class=self-link href=#experimental></a></h3>
<p>To avoid clashes with future CSS features, the CSS2.1 specification
reserves a <a href=http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords>prefixed
syntax</a> for proprietary and experimental extensions to CSS.
<p>Prior to a specification reaching the Candidate Recommendation stage
in the W3C process, all implementations of a CSS feature are considered
experimental. The CSS Working Group recommends that implementations
use a vendor-prefixed syntax for such features, including those in
W3C Working Drafts. This avoids incompatibilities with future changes
in the draft.
</p>
<h3 class="no-ref heading settled heading" id=testing><span class=content>
Non-experimental implementations</span><a class=self-link href=#testing></a></h3>
<p>Once a specification reaches the Candidate Recommendation stage,
non-experimental implementations are possible, and implementors should
release an unprefixed implementation of any CR-level feature they
can demonstrate to be correctly implemented according to spec.
<p>To establish and maintain the interoperability of CSS across
implementations, the CSS Working Group requests that non-experimental
CSS renderers submit an implementation report (and, if necessary, the
testcases used for that implementation report) to the W3C before
releasing an unprefixed implementation of any CSS features. Testcases
submitted to W3C are subject to review and correction by the CSS
Working Group.
<p>Further information on submitting testcases and implementation reports
can be found from on the CSS Working Group’s website at
<a href=http://www.w3.org/Style/CSS/Test/>http://www.w3.org/Style/CSS/Test/</a>.
Questions should be directed to the
<a href=http://lists.w3.org/Archives/Public/public-css-testsuite>public-css-testsuite@w3.org</a>
mailing list.
<h2 class="no-num no-ref heading settled heading" id=references><span class=content>
References</span><a class=self-link href=#references></a></h2>
<h3 class="no-num no-ref heading settled heading" id=normative><span class=content>
Normative References</span><a class=self-link href=#normative></a></h3>
<div data-fill-with=normative-references><dl><dt id=rfc2119 title=RFC2119><a class=self-link href=#rfc2119></a>[RFC2119]<dd>S. Bradner. <a href=http://www.ietf.org/rfc/rfc2119.txt>Key words for use in RFCs to Indicate Requirement Levels</a>. URL: <a href=http://www.ietf.org/rfc/rfc2119.txt>http://www.ietf.org/rfc/rfc2119.txt</a><dt id=selectors4 title=SELECTORS4><a class=self-link href=#selectors4></a>[SELECTORS4]<dd>Elika J. Etemad; Tab Atkins Jr.. <a href=http://www.w3.org/TR/2013/WD-selectors4-20130502/>Selectors Level 4</a>. 2 May 2013. W3C Working Draft. (Work in progress.) URL: <a href=http://www.w3.org/TR/2013/WD-selectors4-20130502/>http://www.w3.org/TR/2013/WD-selectors4-20130502/</a></dl></div>
<h3 class="no-num no-ref heading settled heading" id=informative><span class=content>
Informative References</span><a class=self-link href=#informative></a></h3>
<div data-fill-with=informative-references><dl><dt id=css3syn title=CSS3SYN><a class=self-link href=#css3syn></a>[CSS3SYN]<dd>Tab Atkins Jr.; Simon Sapin. <a href=http://www.w3.org/TR/2013/WD-css-syntax-3-20131105/>CSS Syntax Module</a>. 5 November 2013. W3C Working Draft. (Work in progress.) URL: <a href=http://www.w3.org/TR/2013/WD-css-syntax-3-20131105/>http://www.w3.org/TR/2013/WD-css-syntax-3-20131105/</a><dt id=selectors-api title=SELECTORS-API><a class=self-link href=#selectors-api></a>[SELECTORS-API]<dd>Anne van Kesteren; Lachlan Hunt. <a href=http://www.w3.org/TR/2013/REC-selectors-api-20130221/>Selectors API Level 1</a>. 21 February 2013. W3C Recommendation. URL: <a href=http://www.w3.org/TR/2013/REC-selectors-api-20130221/>http://www.w3.org/TR/2013/REC-selectors-api-20130221/</a></dl></div>
<h2 class="no-num no-ref heading settled heading" id=index><span class=content>
Index</span><a class=self-link href=#index></a></h2>
<div data-fill-with=index><ul class=indexlist>
<li>::attr(), <a href=#selectordef-attr title="section 2.1">2.1</a>
<li>attribute node pseudo-element, <a href=#attribute-node-pseudo-element title="section 2.1">2.1</a>
<li><qualified-name>, <a href=#typedef-qualified-name title="section 2.1">2.1</a>
</ul></div>
<h2 class="no-num no-ref heading settled heading" id=property-index><span class=content>
Property index</span><a class=self-link href=#property-index></a></h2>
<div data-fill-with=property-index><p>No properties defined.</div>