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54 </head>
55 <body>
57 <p><a href="http://www.w3.org/"><img height=48 alt=W3C src="http://www.w3.org/Icons/w3c_home" width=72></a>
63 <dl>
65 <dt>This version:
70 <dt>Latest version:
73 http://www.w3.org/TR/css3-selectors</a>
75 <dt>Previous version:
84 <dd class="vcard"><a lang="tr" class="url fn" href="http://www.tantek.com/">Tantek Çelik</a> (Invited Expert)
95 </dl>
106 <a
108 <a
110 <a
112 use</a> rules apply.
116 </div>
121 tree. Selectors have been optimized for use with HTML and XML, and
122 are designed to be usable in performance-critical code.</p>
125 Style Sheets) is a language for describing the rendering of <acronym
128 screen, on paper, in speech, etc. CSS uses Selectors for binding
129 style properties to elements in the document. This document
130 describes extensions to the selectors defined in CSS level 2. These
131 extended selectors will be used by CSS level 3.
137 <p>That is, given an element and a selector, this specification
138 defines whether that element matches the selector.</p>
140 <p>These expressions can also be used, for instance, to select a set
141 of elements, or a single element from a set of elements, by
142 evaluating the expression across all the elements in a
149 <p><em>This section describes the status of this document at the
150 time of its publication. Other documents may supersede this
151 document. A list of current W3C publications and the latest revision
152 of this technical report can be found in the <a
154 http://www.w3.org/TR/.</a></em></p>
162 <p>The CSS Working Group doesn't expect that all implementations of
163 CSS3 will have to implement all selectors. Instead, there will
164 probably be a small number of variants of CSS3, called profiles. For
165 example, it may be that only a profile for interactive user agents
166 will include all of the selectors.</p>
171 document is a revision of the <a
174 implementation feedback received in the past few years. It is
175 expected that this last call will proceed straight to Proposed
176 Recommendation stage since it is believed that interoperability will
177 be demonstrable.</p>
179 <p>All persons are encouraged to review and implement this
180 specification and return comments to the (<a
182 public mailing list <a
185 Members can also send comments directly to the CSS Working
186 Group.
189 <p>This is still a draft document and may be updated, replaced, or
190 obsoleted by other documents at any time. It is inappropriate to
195 The English version of this specification is the only normative
196 version.
204 <ul>
208 </ul>
218 </ul>
220 <ul>
222 </ul>
225 <li class="tocline4"><a href="#attribute-representation">6.3.1. Representation of attributes and attributes values</a>
229 </ul>
239 <ul>
252 </ul>
254 </ul>
255 </li>
256 </ul>
258 <ul>
263 </ul>
270 <li class="tocline4"><a href="#adjacent-sibling-combinators">8.3.1. Adjacent sibling combinator</a>
271 <li class="tocline4"><a href="#general-sibling-combinators">8.3.2. General sibling combinator</a></li>
272 </ul>
273 </li>
274 </ul>
280 </ul>
287 </ul>
289 </div>
295 <p>Some features of this specification are specific to CSS, or have
296 particular limitations or rules specific to CSS. In this
297 specification, these have been described in terms of CSS2.1. <a
302 <p>All of the text of this specification is normative except
303 examples, notes, and sections explicitly marked as
304 non-normative.</p>
310 <p>The main differences between the selectors in CSS2 and those in
311 Selectors are:
313 <ul>
315 <li>the list of basic definitions (selector, group of selectors,
316 simple selector, etc.) has been changed; in particular, what was
317 referred to in CSS2 as a simple selector is now called a sequence
318 of simple selectors, and the term "simple selector" is now used for
319 the components of this sequence</li>
321 <li>an optional namespace component is now allowed in type element
322 selectors, the universal selector and attribute selectors</li>
326 <li>new simple selectors including substring matching attribute
327 selectors, and new pseudo-classes</li>
330 for pseudo-elements</li>
334 <li>profiles to be added to specifications integrating Selectors
335 and defining the set of selectors which is actually supported by
336 each specification</li>
338 <li>Selectors are now a CSS3 Module and an independent
339 specification; other specifications can now refer to this document
340 independently of CSS</li>
344 </ul>
348 <p><em>This section is non-normative, as it merely summarizes the
349 following sections.</em></p>
351 <p>A Selector represents a structure. This structure can be used as a
352 condition (e.g. in a CSS rule) that determines which elements a
353 selector matches in the document tree, or as a flat description of the
354 HTML or XML fragment corresponding to that structure.</p>
356 <p>Selectors may range from simple element names to rich contextual
357 representations.</p>
362 <thead>
363 <tr>
368 <tbody>
369 <tr>
374 selector</a></td>
376 <tr>
382 <tr>
387 selectors</a></td>
389 <tr>
395 selectors</a></td>
397 <tr>
403 selectors</a></td>
405 <tr>
411 selectors</a></td>
413 <tr>
419 selectors</a></td>
421 <tr>
427 selectors</a></td>
429 <tr>
435 selectors</a></td>
437 <tr>
442 pseudo-classes</a></td>
444 <tr>
449 pseudo-classes</a></td>
451 <tr>
454 from the last one</td>
457 pseudo-classes</a></td>
459 <tr>
464 pseudo-classes</a></td>
466 <tr>
469 from the last one</td>
472 pseudo-classes</a></td>
474 <tr>
479 pseudo-classes</a></td>
481 <tr>
486 pseudo-classes</a></td>
488 <tr>
493 pseudo-classes</a></td>
495 <tr>
500 pseudo-classes</a></td>
502 <tr>
507 pseudo-classes</a></td>
509 <tr>
514 pseudo-classes</a></td>
516 <tr>
519 nodes)</td>
522 pseudo-classes</a></td>
524 <tr>
527 which the target is not yet visited (:link) or already visited
528 (:visited)</td>
531 pseudo-classes</a></td>
533 <tr>
538 action pseudo-classes</a></td>
540 <tr>
545 pseudo-class</a></td>
547 <tr>
550 language specifies how language is determined)</td>
553 pseudo-class</a></td>
555 <tr>
558 disabled</td>
561 pseudo-classes</a></td>
563 <tr>
569 pseudo-classes</a></td>
571 <tr>
576 pseudo-element</a></td>
578 <tr>
583 pseudo-element</a></td>
585 <tr>
588 selected/highlighted by the user</td>
591 fragments pseudo-elements</a></td>
593 <tr>
598 pseudo-element</a></td>
600 <tr>
605 pseudo-element</a></td>
607 <tr>
613 selectors</a></td>
615 <tr>
620 selectors</a></td>
622 <tr>
627 pseudo-class</a></td>
629 <tr>
634 combinator</a></td>
636 <tr>
641 combinator</a></td>
643 <tr>
649 <tr>
656 <p>The meaning of each selector is derived from the table above by
658 column.</p>
662 <p>The case sensitivity of document language element names, attribute
663 names, and attribute values in selectors depends on the document
664 language. For example, in HTML, element names are case-insensitive,
665 but in XML, they are case-sensitive.</p>
678 selector or universal selector is allowed in the sequence.</p>
690 sequence of simple selectors.</p>
695 space may appear between a combinator and the simple selectors around
700 never part of white space.</p>
702 <p>The elements of a document tree that are represented by a selector
704 selector consisting of a single sequence of simple selectors
705 represents any element satisfying its requirements. Prepending another
706 sequence of simple selectors and a combinator to a sequence imposes
707 additional matching constraints, so the subjects of a selector are
708 always a subset of the elements represented by the last sequence of
709 simple selectors.</p>
711 <p>An empty selector, containing no sequence of simple selectors and
717 <p>When several selectors share the same declarations, they may be
722 <p>In this example, we condense three rules with identical
723 declarations into one. Thus,</p>
724 <pre>h1 { font-family: sans-serif }
725 h2 { font-family: sans-serif }
726 h3 { font-family: sans-serif }</pre>
729 </div>
732 because all the selectors are valid selectors. If just one of these
733 selectors were invalid, the entire group of selectors would be
734 invalid. This would invalidate the rule for all three heading
735 elements, whereas in the former case only one of the three individual
736 heading rules would be invalidated.</p>
744 element type. A type selector represents an instance of the element
745 type in the document tree.</p>
751 </div>
758 that has been previously declared may be prepended to the element name
762 <p>The namespace component may be left empty to indicate that the
763 selector is only to represent elements with no declared namespace.</p>
765 <p>An asterisk may be used for the namespace prefix, indicating that
766 the selector represents elements in any namespace (including elements
767 with no namespace).</p>
769 <p>Element type selectors that have no namespace component (no
770 namespace separator), represent elements without regard to the
771 element's namespace (equivalent to "<code>*|</code>") unless a default
772 namespace has been declared. If a default namespace has been declared,
773 the selector will represent only elements in the default
774 namespace.</p>
776 <p>A type selector containing a namespace prefix that has not been
778 The mechanism for declaring a namespace prefix is left up to the
779 language implementing Selectors. In CSS, such a mechanism is defined
780 in the General Syntax module.</p>
782 <p>In a namespace-aware client, element type selectors will only match
783 against the <a
785 of the element's <a
788 behaviors in down-level clients.</p>
792 <dl>
796 <dd>elements with name E in any namespace, including those without any
797 declared namespace</dd>
801 <dd>if no default namespace has been specified, this is equivalent to *|E.
802 Otherwise it is equivalent to ns|E where ns is the default namespace.</dd>
803 </dl>
808 <pre>@namespace foo url(http://www.example.com);
809 foo|h1 { color: blue }
810 foo|* { color: yellow }
811 |h1 { color: red }
812 *|h1 { color: green }
813 h1 { color: green }</pre>
818 <p>The second rule will match all elements in the
822 any declared namespace.</p>
825 namespace (including those without any declared namespace).</p>
827 <p>The last rule is equivalent to the fourth rule because no default
828 namespace has been defined.</p>
830 </div>
836 type. It represents any single element in the document tree in any
837 namespace (including those without any declared namespace) if no
838 default namespace has been specified. If a default namespace has been
842 <p>If the universal selector is not the only component of a sequence
847 <ul>
851 </ul>
852 </div>
856 omitted.</p>
860 <p>The universal selector allows an optional namespace component. It
861 is used as follows:</p>
863 <dl>
871 <dd>if no default namespace has been specified, this is equivalent to *|*.
872 Otherwise it is equivalent to ns|* where ns is the default namespace.</dd>
873 </dl>
875 <p>A universal selector containing a namespace prefix that has not
877 selector. The mechanism for declaring a namespace prefix is left up
878 to the language implementing Selectors. In CSS, such a mechanism is
879 defined in the General Syntax module.</p>
884 <p>Selectors allow the representation of an element's attributes. When
885 a selector is used as an expression to match against an element,
886 attribute selectors must be considered to match an element if that
887 element has an attribute that matches the attribute represented by the
888 attribute selector.</p>
891 selectors</a></h4>
895 <dl>
898 the attribute.</dd>
907 spaces).</dd>
917 </dl>
919 <p>Attribute values must be identifiers or strings. The
920 case-sensitivity of attribute names and values in selectors depends on
921 the document language.</p>
929 value:</p>
933 <p>In the following example, the selector represents a
939 <p>Multiple attribute selectors can be used to represent several
940 attributes of an element, or several conditions on the same
949 and "~=". The first selector will represent, for example, the value
969 <p>Similarly, the following selectors represents a
973 <pre>DIALOGUE[character=romeo]
974 DIALOGUE[character=juliet]</pre>
976 </div>
979 selectors</h4>
981 <p>Three additional attribute selectors are provided for matching
982 substrings in the value of an attribute:</p>
984 <dl>
994 </dl>
996 <p>Attribute values must be identifiers or strings. The
997 case-sensitivity of attribute names in selectors depends on the
998 document language.</p>
1003 image:</p>
1011 </div>
1015 <p>Attribute selectors allow an optional namespace component to the
1016 attribute name. A namespace prefix that has been previously declared
1017 may be prepended to the attribute name separated by the namespace
1019 the Namespaces in the XML recommendation, default namespaces do not
1020 apply to attributes, therefore attribute selectors without a namespace
1021 component apply only to attributes that have no declared namespace
1022 (equivalent to "<code>|attr</code>"). An asterisk may be used for the
1023 namespace prefix indicating that the selector is to match all
1024 attribute names without regard to the attribute's namespace.
1026 <p>An attribute selector with an attribute name containing a namespace
1027 prefix that has not been previously declared is an <a
1029 a namespace prefix is left up to the language implementing Selectors.
1030 In CSS, such a mechanism is defined in the General Syntax module.
1035 [foo|att=val] { color: blue }
1036 [*|att] { color: yellow }
1037 [|att] { color: green }
1038 [att] { color: green }</pre>
1040 <p>The first rule will match only elements with the attribute
1044 <p>The second rule will match only elements with the attribute
1046 (including no declared namespace).</p>
1048 <p>The last two rules are equivalent and will match only elements
1050 declared to be in a namespace.</p>
1052 </div>
1056 <p>Attribute selectors represent explicitly set attribute values in
1057 the document tree. Default attribute values may be defined in a DTD or
1058 elsewhere, but cannot always be selected by attribute
1059 selectors. Selectors should be designed so that they work even if the
1060 default values are not included in the document tree.</p>
1069 knowledge of that namespace to treat default attribute values as if
1070 they were present in the document. (For example, an XHTML UA is not
1071 required to use its built-in knowledge of the XHTML DTD.)</p>
1074 choose to ignore external subsets.</p>
1086 <pre>EXAMPLE[notation=decimal] { /*... default property settings ...*/ }
1087 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre>
1090 is set by default, i.e. not set explicitly. To catch all cases, the
1091 attribute selector for the default value must be dropped:</p>
1093 <pre>EXAMPLE { /*... default property settings ...*/ }
1094 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre>
1097 more specific than the tag
1098 selector alone, the style declarations in the second rule will override
1099 those in the first for elements that have a "notation" attribute value
1100 of "octal". Care has to be taken that all property declarations that
1101 are to apply only to the default case are overridden in the non-default
1102 cases' style rules.</p>
1104 </div>
1112 the same meaning. The attribute value must immediately follow the
1115 <p>UAs may apply selectors using the period (.) notation in XML
1116 documents if the UA has namespace-specific knowledge that allows it to
1118 respective namespace. One such example of namespace-specific knowledge
1119 is the prose in the specification for a particular namespace (e.g. SVG
1130 <p>We can assign style information to all elements with
1139 <p>The following assigns style only to H1 elements with
1144 <p>Given these rules, the first H1 instance below would not have
1145 green text, while the second would:</p>
1150 </div>
1160 has been assigned a list of <a
1170 </div>
1173 power to the "class" attribute, authors could conceivably design their
1174 own "document language" based on elements with almost no associated
1175 presentation (such as DIV and SPAN in HTML) and assigning style
1176 information through the "class" attribute. Authors should avoid this
1177 practice since the structural elements of a document language often
1178 have recognized and accepted meanings and author-defined classes may
1179 not.</p>
1182 class attributes, their values must be concatenated with spaces
1183 between the values before searching for the class. As of this time the
1184 working group is not aware of any manner in which this situation can
1185 be reached, however, so this behavior is explicitly non-normative in
1186 this specification.</p>
1190 <p>Document languages may contain attributes that are declared to be
1191 of type ID. What makes attributes of type ID special is that no two
1192 such attributes can have the same value in a document, regardless of
1193 the type of the elements that carry them; whatever the document
1194 language, an ID typed attribute can be used to uniquely identify its
1195 element. In HTML all ID attributes are named "id"; XML applications
1196 may name ID attributes differently, but the same restriction
1197 applies.</p>
1199 <p>An ID-typed attribute of a document language allows authors to
1200 assign an identifier to one element instance in the document tree. W3C
1201 ID selectors represent an element instance based on its identifier. An
1204 identifier.</p>
1206 <p>Selectors does not specify how a UA knows the ID-typed attribute of
1207 an element. The UA may, e.g., read a document's DTD, have the
1208 information hard-coded or ask the user.
1215 <p>The following ID selector represents any element whose ID-typed
1218 <p>The following selector represents any element whose ID-typed
1221 </div>
1225 contains an element's IDs is contained in a DTD or a schema. When
1226 parsing XML, UAs do not always read the DTD, and thus may not know
1227 what the ID of an element is (though a UA may have namespace-specific
1228 knowledge that allows it to determine which attribute is the ID
1229 attribute for that namespace). If a style sheet designer knows or
1230 suspects that a UA may not know what the ID of an element is, he
1231 should use normal attribute selectors instead:
1235 <p>If an element has multiple ID attributes, all of them must be
1236 treated as IDs for that element for the purposes of the ID
1237 selector. Such a situation could be reached using mixtures of xml:id,
1238 DOM3 Core, XML DTDs, and namespace-specific knowledge.</p>
1242 <p>The pseudo-class concept is introduced to permit selection based on
1243 information that lies outside of the document tree or that cannot be
1244 expressed using the other simple selectors.</p>
1248 optionally by a value between parentheses.</p>
1250 <p>Pseudo-classes are allowed in all sequences of simple selectors
1251 contained in a selector. Pseudo-classes are allowed anywhere in
1252 sequences of simple selectors, after the leading type selector or
1253 universal selector (possibly omitted). Pseudo-class names are
1254 case-insensitive. Some pseudo-classes are mutually exclusive, while
1255 others can be applied simultaneously to the same
1256 element. Pseudo-classes may be dynamic, in the sense that an element
1257 may acquire or lose a pseudo-class while a user interacts with the
1258 document.</p>
1263 <p>Dynamic pseudo-classes classify elements on characteristics other
1264 than their name, attributes, or content, in principle characteristics
1265 that cannot be deduced from the document tree.</p>
1267 <p>Dynamic pseudo-classes do not appear in the document source or
1268 document tree.</p>
1273 <p>User agents commonly display unvisited links differently from
1274 previously visited ones. Selectors
1278 <ul>
1280 not yet been visited.</li>
1282 been visited by the user. </li>
1283 </ul>
1285 <p>After some amount of time, user agents may choose to return a
1286 visited link to the (unvisited) ':link' state.</p>
1294 <p>The following selector represents links carrying class
1299 </div>
1302 authors to abuse the :link and :visited pseudo-classes to determine
1303 which sites a user has visited without the user's consent.
1305 <p>UAs may therefore treat all links as unvisited links, or implement
1306 other measures to preserve the user's privacy while rendering visited
1307 and unvisited links differently.</p>
1310 :hover, :active, and :focus</a></h5>
1312 <p>Interactive user agents sometimes change the rendering in response
1313 to user actions. Selectors provides
1314 three pseudo-classes for the selection of an element the user is
1315 acting on.</p>
1317 <ul>
1320 designates an element with a pointing device, but does not activate
1321 it. For example, a visual user agent could apply this pseudo-class
1322 when the cursor (mouse pointer) hovers over a box generated by the
1323 element. User agents not that do not support <a
1325 media</a> do not have to support this pseudo-class. Some conforming
1326 user agents that support <a
1328 media</a> may not be able to support this pseudo-class (e.g., a pen
1329 device that does not detect hovering).</li>
1332 is being activated by the user. For example, between the times the
1333 user presses the mouse button and releases it.</li>
1336 has the focus (accepts keyboard or mouse events, or other forms of
1337 input). </li>
1339 </ul>
1341 <p>There may be document language or implementation specific limits on
1345 <p>These pseudo-classes are not mutually exclusive. An element may
1346 match several pseudo-classes at the same time.</p>
1348 <p>Selectors doesn't define if the parent of an element that is
1349 ':active' or ':hover' is also in that state.</p>
1353 <pre>a:link /* unvisited links */
1354 a:visited /* visited links */
1355 a:hover /* user hovers */
1356 a:active /* active links */</pre>
1358 <pre>a:focus
1359 a:focus:hover</pre>
1361 the pseudo-class :focus and in the pseudo-class :hover.</p>
1362 </div>
1365 and ':active' (or ':link' and ':active').</p>
1369 <p>Some URIs refer to a location within a resource. This kind of URI
1371 identifier (called the fragment identifier).</p>
1373 <p>URIs with fragment identifiers link to a certain element within the
1374 document, known as the target element. For instance, here is a URI
1376 document:</p>
1381 pseudo-class. If the document's URI has no fragment identifier, then
1382 the document has no target element.</p>
1389 URI.</p>
1390 </div>
1395 target element red and place an image before it, if there is one:</p>
1396 <pre>*:target { color : red }
1397 *:target::before { content : url(target.png) }</pre>
1398 </div>
1402 <p>If the document language specifies how the human language of an
1403 element is determined, it is possible to write selectors that
1404 represent an element based on its language. For example, in HTML <a
1407 element, and possibly by information from the protocol (such as HTTP
1409 there may be other document language-specific methods for determining
1410 the language.</p>
1413 is in language C. Whether an element is represented by a
1415 being either equal to, or a hyphen-separated substring of, the
1416 element's language value, in the same way as if performed by the <a
1418 selectors. The identifier C does not have to be a valid language
1419 name.</p>
1433 <p>The two following selectors represent an HTML document that is in
1434 Belgian, French, or German. The two next selectors represent
1436 or German.</p>
1437 <pre>html:lang(fr-be)
1438 html:lang(de)
1439 :lang(fr-be) > q
1441 </div>
1448 the look of user interface elements that are enabled — which the
1449 user can select or activate in some fashion (e.g. clicking on a button
1450 with a mouse). There is a need for such a pseudo-class because there
1451 is no way to programmatically specify the default appearance of say,
1453 would look like when it was disabled.</p>
1456 author to specify precisely how a disabled or inactive user interface
1457 element should look.</p>
1459 <p>Most elements will be neither enabled nor disabled. An element is
1460 enabled if the user can either activate it or transfer the focus to
1461 it. An element is disabled if it could be enabled, but the user cannot
1462 presently activate it or transfer focus to it.</p>
1467 <p>Radio and checkbox elements can be toggled by the user. Some menu
1468 items are "checked" when the user selects them. When such elements are
1472 attributes as described in <a
1477 in nature, and is altered by user action, since it can also be based
1486 <p>Radio and checkbox elements can be toggled by the user, but are
1487 sometimes in an indeterminate state, neither checked nor unchecked.
1488 This can be due to an element attribute, or DOM manipulation.</p>
1490 <p>A future version of this specification may introduce an
1492 <!--While the <code>:indeterminate</code> pseudo-class is dynamic in
1493 nature, and is altered by user action, since it can also be based on
1494 the presence of an element attribute, it applies to all media.</p>
1496 <p>Components of a radio-group initialized with no pre-selected choice
1499 </div>
1505 pseudo-classes</dfn> to permit selection based on extra information that lies in
1506 the document tree but cannot be represented by other simple selectors or
1507 combinators.
1509 <p>Note that standalone pieces of PCDATA (text nodes in the DOM) are
1510 not counted when calculating the position of an element in the list of
1511 children of its parent. When calculating the position of an element in
1512 the list of children of its parent, the index numbering starts at 1.
1518 the root of the document. In HTML 4, this is always the
1524 <p>The
1526 pseudo-class notation represents an element that has
1532 each. For example, this allows the selectors to address every other
1533 row in a table, and could be used to alternate the color
1536 integers. The index of the first child of an element is 1.
1547 tr:nth-child(odd) /* same */
1548 tr:nth-child(2n) /* represents every even row of an HTML table */
1549 tr:nth-child(even) /* same */
1551 /* Alternate paragraph colours in CSS */
1556 </div>
1561 included, so the syntax simplifies to
1569 </div>
1577 bar:nth-child(n+0) /* same */
1578 bar:nth-child(n) /* same */
1580 </div>
1589 </div>
1592 pseudo-class represents no element in the document tree.</p>
1597 tree.</p>
1602 </div>
1605 expression must be removed (it is effectively replaced by the "-"
1613 </div>
1619 pseudo-class notation represents an element that has
1625 as arguments.
1632 foo:nth-last-child(odd) /* represents all odd foo elements in their parent element,
1633 counting from the last one */</pre>
1634 </div>
1640 pseudo-class notation represents an element that has
1645 of that type after all the children of that type have been split into
1647 for the syntax of its argument. It also accepts the
1656 </div>
1662 pseudo-class notation represents an element that has
1674 following selector:</p>
1677 selector ends up being just as long:</p>
1679 </div>
1685 represents an element that is the first child of some other element.
1699 fragment:
1707 a:first-child /* Same (assuming a is not the root element) */</pre>
1708 </div>
1713 represents an element that is the last child of some other element.
1720 </div>
1725 represents an element that is the first sibling of its type in the list of
1726 children of its parent element.
1730 <p>The following selector represents a definition title
1733 its parent element.</p>
1736 elements in the following example but not for the third one:</p>
1748 </div>
1754 the last sibling of its type in the list of children of its parent
1755 element.</p>
1759 <p>The following selector represents the last data cell
1762 </div>
1766 <p>Represents an element that has a parent element and whose parent
1767 element has no other element children. Same as
1770 specificity.</p>
1774 <p>Represents an element that has a parent element and whose parent
1775 element has no other element children with the same element name. Same
1778 specificity.</p>
1784 no children at all. In terms of the DOM, only element nodes and text
1785 nodes (including CDATA nodes and entity references) whose data has a
1786 non-zero length must be considered as affecting emptiness; comments,
1787 PIs, and other nodes must not affect whether an element is considered
1788 empty or not.</p>
1795 following fragments:</p>
1799 </div>
1801 <h4><a name=content-selectors>6.6.6. Blank</a></h4> <!-- It's the Return of Appendix H!!! Run away! -->
1804 <!-- (used to be :contains()) -->
1810 selector</a> (excluding the negation pseudo-class itself and
1811 pseudo-elements) as an argument. It represents an element that is not
1812 represented by the argument.
1814 <!-- pseudo-elements are not simple selectors, so the above paragraph
1815 may be a bit confusing -->
1820 elements in an HTML document that are not disabled.</p>
1823 elements.</p>
1825 <p>The following group of selectors represents all HTML elements
1826 except links.</p>
1828 </div>
1830 <p>Default namespace declarations do not affect the argument of the
1831 negation pseudo-class unless the argument is a universal selector or a
1832 type selector.</p>
1836 <p>Assuming that the default namespace is bound to
1837 "http://example.com/", the following selector represents all
1838 elements that are not in that namespace:</p>
1840 <p>The following CSS selector matches any element being hovered,
1841 regardless of its namespace. In particular, it is not limited to
1842 only matching elements in the default namespace that are not being
1843 hovered, and elements not in the default namespace don't match the
1846 </div>
1852 specificity.</p>
1856 <p>Pseudo-elements create abstractions about the document tree beyond
1857 those specified by the document language. For instance, document
1858 languages do not offer mechanisms to access the first letter or first
1859 line of an element's content. Pseudo-elements allow designers to refer
1860 to this otherwise inaccessible information. Pseudo-elements may also
1861 provide designers a way to refer to content that does not exist in the
1864 content).</p>
1867 by the name of the pseudo-element.</p>
1870 in order to establish a discrimination between pseudo-classes and
1871 pseudo-elements. For compatibility with existing style sheets, user
1872 agents must also accept the previous one-colon notation for
1878 <p>Only one pseudo-element may appear per selector, and if present it
1879 must appear after the sequence of simple selectors that represents the
1881 future version of this specification may allow multiple
1882 pesudo-elements per selector.</span></p>
1887 of the first formatted line of an element.
1894 </div>
1897 HTML element. It does match a pseudo-element that conforming user
1898 agents will insert at the beginning of every paragraph.</p>
1900 <p>Note that the length of the first line depends on a number of
1901 factors, including the width of the page, the font size, etc. Thus,
1902 an ordinary HTML paragraph such as:</p>
1904 <pre>
1906 paragraph that will be broken into several
1907 lines. The first line will be identified
1908 by a fictional tag sequence. The other lines
1909 will be treated as ordinary lines in the
1911 </pre>
1913 <p>the lines of which happen to be broken as follows:
1915 <pre>
1916 THIS IS A SOMEWHAT LONG HTML PARAGRAPH THAT
1917 will be broken into several lines. The first
1918 line will be identified by a fictional tag
1919 sequence. The other lines will be treated as
1920 ordinary lines in the paragraph.
1921 </pre>
1925 fictional tag sequence helps to show how properties are inherited.</p>
1927 <pre>
1930 lines. The first line will be identified
1931 by a fictional tag sequence. The other lines
1932 will be treated as ordinary lines in the
1934 </pre>
1936 <p>If a pseudo-element breaks up a real element, the desired effect
1937 can often be described by a fictional tag sequence that closes and
1938 then re-opens the element. Thus, if we mark up the previous paragraph
1941 <pre>
1943 paragraph that will be broken into several
1945 by a fictional tag sequence. The other lines
1946 will be treated as ordinary lines in the
1948 </pre>
1950 <p>the user agent could simulate start and end tags for
1954 <pre>
1956 somewhat long HTML
1957 paragraph that will <b></SPAN></b></P::first-line><b><SPAN class="test"></b> be
1958 broken into several
1960 by a fictional tag sequence. The other lines
1961 will be treated as ordinary lines in the
1963 </pre>
1966 attached to a block-level element, an inline-block, a table-caption,
1967 or a table-cell.</p>
1970 element may occur inside a
1971 block-level descendant in the same flow (i.e., a block-level
1972 descendant that is not positioned and not a float). E.g., the first
1977 <p>The first line of a table-cell or inline-block cannot be the first
1988 <p>A UA should act as if the fictional start tags of the
1990 innermost enclosing block-level element. (Since CSS1 and CSS2 were
1991 silent on this case, authors should not rely on this behavior.) Here
1992 is an example. The fictional tag sequence for</p>
1994 <pre>
1999 </pre>
2003 <pre>
2005 <P><DIV::first-line><P::first-line>First paragraph</P::first-line></DIV::first-line></P>
2008 </pre>
2011 inline-level element, but with certain restrictions. In CSS, the
2013 pseudo-element: font properties, color property, background
2014 properties, 'word-spacing', 'letter-spacing', 'text-decoration',
2015 'vertical-align', 'text-transform', 'line-height'. UAs may apply other
2016 properties as well.</p>
2022 letter of the first line of a block, if it is not preceded by any
2023 other content (such as images or inline tables) on its line. The
2025 caps", which are common typographical effects. This type of initial
2026 letter is similar to an inline-level element if its 'float' property
2027 is 'none'; otherwise, it is similar to a floated element.</p>
2030 pseudo-elements: font properties, 'text-decoration', 'text-transform',
2031 'letter-spacing', 'word-spacing' (when appropriate), 'line-height',
2032 'float', 'vertical-align' (only if 'float' is 'none'), margin
2033 properties, padding properties, border properties, color property,
2034 background properties. UAs may apply other properties as well. To
2035 allow UAs to render a typographically correct drop cap or initial cap,
2036 the UA may choose a line-height, width and height based on the shape
2037 of the letter, unlike for normal elements.</p>
2041 <p>This example shows a possible rendering of an initial cap. Note
2043 pseudo-element is 1.1, but the UA in this example has computed the
2044 height of the first letter differently, so that it doesn't cause any
2045 unnecessary space between the first two lines. Also note that the
2048 <pre>
2049 p { line-height: 1.1 }
2050 p::first-letter { font-size: 3em; font-weight: normal }
2051 span { font-weight: bold }
2052 ...
2056 En dagelix geschrey de bange stad ontzet.
2057 </pre>
2060 </div>
2061 </div>
2066 <pre>
2073 P::first-letter { font-size: 200%; font-weight: bold; float: left }
2074 SPAN { text-transform: uppercase }
2082 </pre>
2087 <P><img src="first-letter.gif" alt="Image illustrating the combined effect of the ::first-letter and ::first-line pseudo-elements"></p>
2088 </div>
2093 <pre>
2097 T
2100 few words of an article in the Economist.
2102 </pre>
2105 the content (i.e., the initial character), while the ::first-line
2106 pseudo-element start tag is inserted right after the start tag of the
2107 block element.</p> </div>
2109 <p>In order to achieve traditional drop caps formatting, user agents
2110 may approximate font sizes, for example to align baselines. Also, the
2111 glyph outline may be taken into account when formatting.</p>
2115 punctuation classes), that precedes or follows the first letter should
2121 </div>
2128 block, list-item, table-cell, table-caption, and inline-block
2130 may allow this pesudo-element to apply to more element
2131 types.</span></p>
2134 such elements that contain text, or that have a descendant in the same
2135 flow that contains text. A UA should act as if the fictional start tag
2136 of the ::first-letter pseudo-element is just before the first text of
2137 the element, even if that first text is in a descendant.</p>
2141 <p>The fictional tag sequence for this HTMLfragment:
2144 <p>is:
2147 </div>
2149 <p>The first letter of a table-cell or inline-block cannot be the
2162 <p>In CSS, if an element is a list item ('display: list-item'), the
2164 principal box after the marker. UAs may ignore
2174 </div>
2176 <p>Some languages may have specific rules about how to treat certain
2177 letter combinations. In Dutch, for example, if the letter combination
2178 "ij" appears at the beginning of a word, both letters should be
2181 <p>If the letters that would form the ::first-letter are not in the
2183 may create a ::first-letter pseudo-element from one of the elements,
2184 both elements, or simply not create a pseudo-element.</p>
2186 <p>Similarly, if the first letter(s) of the block are not at the start
2187 of the line (for example due to bidirectional reordering), then the UA
2188 need not create the pseudo-element(s).
2193 how overlapping pseudo-elements may interact. The first letter of
2194 each P element will be green with a font size of '24pt'. The rest of
2195 the first formatted line will be 'blue' while the rest of the
2196 paragraph will be 'red'.</p>
2199 p::first-letter { color: green; font-size: 200% }
2200 p::first-line { color: blue }
2211 S
2214 ends up on two lines
2221 </div>
2227 of a document that has been highlighted by the user. This also
2228 applies, for example, to selected text within an editable text
2229 field. This pseudo-element should not be confused with the <code><a
2234 nature, and is altered by user action, it is reasonable to expect that
2235 when a UA re-renders to a static medium (such as a printed page, see
2237 dynamic medium (like screen), the UA may wish to transfer the current
2239 appropriate formatting and rendering take effect as well. This is not
2241 pseudo-element for static media.
2244 pseudo-elements: color, background, cursor (optional), outline
2245 (optional). The computed value of the 'background-image' property on
2252 can be used to describe generated content before or after an element's
2259 element including the inserted text.</p>
2265 <p>At times, authors may want selectors to describe an element that is
2266 the descendant of another element in the document tree (e.g., "an
2267 <code>EM</code> element that is contained within an <code>H1</code>
2268 element"). Descendant combinators express such a relationship. A
2270 separates two sequences of simple selectors. A selector of the form
2280 description of the following fragment:</p>
2287 either side of the "*" is not part of the universal selector; the
2288 whitespace is a combinator indicating that the DIV must be the
2289 ancestor of some element, and that that element must be an ancestor
2290 of the P.</p>
2291 <p>The following selector, which combines descendant combinators and
2296 </div>
2301 between two elements. A child combinator is made of the
2303 separates two sequences of simple selectors.
2311 <p>The following example combines descendant combinators and child
2312 combinators.</p>
2319 </div>
2321 <p>For information on selecting the first child of an element, please
2322 see the section on the <code><a
2324 above.</p>
2328 <p>There are two different sibling combinators: the adjacent sibling
2329 combinator and the general sibling combinator. In both cases,
2330 non-element nodes (e.g. text between elements) are ignored when
2331 considering adjacency of elements.</p>
2337 sequences of simple selectors. The elements represented by the two
2338 sequences share the same parent in the document tree and the element
2339 represented by the first sequence immediately precedes the element
2340 represented by the second one.</p>
2347 <p>The following selector is conceptually similar to the one in the
2348 previous example, except that it adds an attribute selector — it
2352 </div>
2359 simple selectors. The elements represented by the two sequences share
2360 the same parent in the document tree and the element represented by
2361 the first sequence precedes (not necessarily immediately) the element
2362 represented by the second one.</p>
2368 is a correct and valid, but partial, description of:</p>
2372 </div>
2378 <ul>
2380 <li>count the number of class selectors, attributes selectors, and pseudo-classes in the selector (= b)</li>
2383 </ul>
2386 are counted like any other, but the negation itself does not count as
2387 a pseudo-class.</p>
2389 <p>Concatenating the three numbers a-b-c (in a number system with a
2390 large base) gives the specificity.</p>
2403 </pre>
2404 </div>
2414 <p>The grammar below defines the syntax of Selectors. It is globally
2416 it directly, since it doesn't express the parsing conventions). The
2417 format of the productions is optimized for human consumption and some
2419 are used:</p>
2421 <ul>
2427 </ul>
2431 <pre>selectors_group
2432 : selector [ COMMA S* selector ]*
2433 ;
2435 selector
2436 : simple_selector_sequence [ combinator simple_selector_sequence ]*
2437 ;
2439 combinator
2440 /* combinators can be surrounded by white space */
2441 : PLUS S* | GREATER S* | TILDE S* | S+
2442 ;
2444 simple_selector_sequence
2445 : [ type_selector | universal ]
2446 [ HASH | class | attrib | pseudo | negation ]*
2447 | [ HASH | class | attrib | pseudo | negation ]+
2448 ;
2450 type_selector
2451 : [ namespace_prefix ]? element_name
2452 ;
2454 namespace_prefix
2455 : [ IDENT | '*' ]? '|'
2456 ;
2458 element_name
2459 : IDENT
2460 ;
2462 universal
2463 : [ namespace_prefix ]? '*'
2464 ;
2466 class
2467 : '.' IDENT
2468 ;
2470 attrib
2471 : '[' S* [ namespace_prefix ]? IDENT S*
2472 [ [ PREFIXMATCH |
2473 SUFFIXMATCH |
2474 SUBSTRINGMATCH |
2475 '=' |
2476 INCLUDES |
2477 DASHMATCH ] S* [ IDENT | STRING ] S*
2478 ]? ']'
2479 ;
2481 pseudo
2482 /* '::' starts a pseudo-element, ':' a pseudo-class */
2483 /* Exceptions: :first-line, :first-letter, :before and :after. */
2484 /* Note that pseudo-elements are restricted to one per selector and */
2485 /* occur only in the last simple_selector_sequence. */
2486 : ':' ':'? [ IDENT | functional_pseudo ]
2487 ;
2489 functional_pseudo
2490 : FUNCTION S* expression ')'
2491 ;
2493 expression
2494 /* In CSS3, the expressions are identifiers, strings, */
2495 /* or of the form "an+b" */
2496 : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
2497 ;
2499 negation
2500 : NOT S* negation_arg S* ')'
2501 ;
2503 negation_arg
2504 : type_selector | universal | HASH | class | attrib | pseudo
2505 ;</pre>
2512 case-insensitive.</p>
2515 number that current versions of Flex can deal with (decimal 255). They
2520 <pre>%option case-insensitive
2522 ident [-]?{nmstart}{nmchar}*
2523 name {nmchar}+
2524 nmstart [_a-z]|{nonascii}|{escape}
2527 escape {unicode}|\\[^\n\r\f0-9a-f]
2528 nmchar [_a-z0-9-]|{nonascii}|{escape}
2530 string {string1}|{string2}
2532 string2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\'
2533 invalid {invalid1}|{invalid2}
2535 invalid2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*
2536 nl \n|\r\n|\r|\f
2537 w [ \t\r\n\f]*
2539 %%
2541 [ \t\r\n\f]+ return S;
2548 {ident} return IDENT;
2549 {string} return STRING;
2551 {num} return NUMBER;
2558 @{ident} return ATKEYWORD;
2559 {invalid} return INVALID;
2560 {num}% return PERCENTAGE;
2561 {num}{ident} return DIMENSION;
2567 U\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})? return UNICODE_RANGE;
2569 \/\*[^*]*\*+([^/*][^*]*\*+)*\/ /* ignore comments */
2571 . return *yytext;</pre>
2575 <h2><a name=downlevel>11. Namespaces and down-level clients</a></h2>
2577 <p>An important issue is the interaction of CSS selectors with XML
2578 documents in web clients that were produced prior to this
2579 document. Unfortunately, due to the fact that namespaces must be
2580 matched based on the URI which identifies the namespace, not the
2581 namespace prefix, some mechanism is required to identify namespaces in
2582 CSS by their URI as well. Without such a mechanism, it is impossible
2583 to construct a CSS style sheet which will properly match selectors in
2584 all cases against a random set of XML documents. However, given
2585 complete knowledge of the XML document to which a style sheet is to be
2586 applied, and a limited use of namespaces within the XML document, it
2587 is possible to construct a style sheet in which selectors would match
2588 elements and attributes correctly.</p>
2590 <p>It should be noted that a down-level CSS client will (if it
2591 properly conforms to CSS forward compatible parsing rules) ignore all
2592 <code>@namespace</code> at-rules, as well as all style rules that make
2593 use of namespace qualified element type or attribute selectors. The
2594 syntax of delimiting namespace prefixes in CSS was deliberately chosen
2595 so that down-level CSS clients would ignore the style rules rather
2596 than possibly match them incorrectly.</p>
2598 <p>The use of default namespaces in CSS makes it possible to write
2599 element type selectors that will function in both namespace aware CSS
2600 clients as well as down-level clients. It should be noted that
2601 down-level clients may incorrectly match selectors against XML
2602 elements in other namespaces.</p>
2604 <p>The following are scenarios and examples in which it is possible to
2605 construct style sheets which would function properly in web clients
2606 that do not implement this proposal.</p>
2608 <ol>
2609 <li>
2611 <p>The XML document does not use namespaces.</p>
2613 <ul>
2615 <li>In this case, it is obviously not necessary to declare or use
2616 namespaces in the style sheet. Standard CSS element type and
2617 attribute selectors will function adequately in a down-level
2618 client.</li>
2620 <li>In a CSS namespace aware client, the default behavior of
2621 element selectors matching without regard to namespace will
2622 function properly against all elements, since no namespaces are
2623 present. However, the use of specific element type selectors that
2625 will guarantee that selectors will match only XML elements that do
2626 not have a declared namespace. </li>
2628 </ul>
2630 </li>
2632 <li>
2634 <p>The XML document defines a single, default namespace used
2635 throughout the document. No namespace prefixes are used in element
2636 names.</p>
2638 <ul>
2640 <li>In this case, a down-level client will function as if
2641 namespaces were not used in the XML document at all. Standard CSS
2642 element type and attribute selectors will match against all
2643 elements. </li>
2645 </ul>
2647 </li>
2649 <li>
2651 <p>The XML document does <b>not</b> use a default namespace, all
2652 namespace prefixes used are known to the style sheet author, and
2653 there is a direct mapping between namespace prefixes and namespace
2654 URIs. (A given prefix may only be mapped to one namespace URI
2655 throughout the XML document; there may be multiple prefixes mapped
2656 to the same URI).</p>
2658 <ul>
2660 <li>In this case, the down-level client will view and match
2661 element type and attribute selectors based on their fully
2662 qualified name, not the local part as outlined in the <a
2665 to describe the fully qualified names, e.g.
2667 <code><html:h1></code>. Selectors using the qualified name
2668 will only match XML elements that use the same prefix. Other
2669 namespace prefixes used in the XML that are mapped to the same URI
2670 will not match as expected unless additional CSS style rules are
2671 declared for them.</li>
2673 <li>Note that selectors declared in this fashion will
2674 <em>only</em> match in down-level clients. A CSS namespace aware
2675 client will match element type and attribute selectors based on
2676 the name's local part. Selectors declared with the fully
2677 qualified name will not match (unless there is no namespace prefix
2678 in the fully qualified name).</li>
2680 </ul>
2682 </li>
2684 </ol>
2686 <p>In other scenarios: when the namespace prefixes used in the XML are
2687 not known in advance by the style sheet author; or a combination of
2688 elements with no namespace are used in conjunction with elements using
2689 a default namespace; or the same namespace prefix is mapped to
2690 <em>different</em> namespace URIs within the same document, or in
2691 different documents; it is impossible to construct a CSS style sheet
2692 that will function properly against all elements in those documents,
2693 unless, the style sheet is written using a namespace URI syntax (as
2694 outlined in this document or similar) and the document is processed by
2695 a CSS and XML namespace aware client.</p>
2697 <h2><a name=profiling>12. Profiles</a></h2>
2699 <p>Each specification using Selectors must define the subset of W3C
2700 Selectors it allows and excludes, and describe the local meaning of
2701 all the components of that subset.</p>
2703 <p>Non normative examples:
2707 <tbody>
2708 <tr>
2710 <tr>
2711 <th>Specification</th>
2712 <td>CSS level 1</td></tr>
2713 <tr>
2714 <th>Accepts</th>
2715 <td>type selectors<br>class selectors<br>ID selectors<br>:link,
2716 :visited and :active pseudo-classes<br>descendant combinator
2717 <br>::first-line and ::first-letter pseudo-elements</td></tr>
2718 <tr>
2719 <th>Excludes</th>
2720 <td>
2722 <p>universal selector<br>attribute selectors<br>:hover and :focus
2723 pseudo-classes<br>:target pseudo-class<br>:lang() pseudo-class<br>all UI
2724 element states pseudo-classes<br>all structural
2725 pseudo-classes<br>negation pseudo-class<br>all
2726 UI element fragments pseudo-elements<br>::before and ::after
2727 pseudo-elements<br>child combinators<br>sibling combinators
2729 <p>namespaces</td></tr>
2730 <tr>
2731 <th>Extra constraints</th>
2732 <td>only one class selector allowed per sequence of simple
2733 selectors</td></tr></tbody></table><br><br>
2735 <tbody>
2736 <tr>
2738 <tr>
2739 <th>Specification</th>
2740 <td>CSS level 2</td></tr>
2741 <tr>
2742 <th>Accepts</th>
2743 <td>type selectors<br>universal selector<br>attribute presence and
2744 values selectors<br>class selectors<br>ID selectors<br>:link, :visited,
2745 :active, :hover, :focus, :lang() and :first-child pseudo-classes
2746 <br>descendant combinator<br>child combinator<br>adjacent sibling
2747 combinator<br>::first-line and ::first-letter pseudo-elements<br>::before
2748 and ::after pseudo-elements</td></tr>
2749 <tr>
2750 <th>Excludes</th>
2751 <td>
2753 <p>content selectors<br>substring matching attribute
2754 selectors<br>:target pseudo-classes<br>all UI element
2755 states pseudo-classes<br>all structural pseudo-classes other
2756 than :first-child<br>negation pseudo-class<br>all UI element
2757 fragments pseudo-elements<br>general sibling combinators
2759 <p>namespaces</td></tr>
2760 <tr>
2761 <th>Extra constraints</th>
2762 <td>more than one class selector per sequence of simple selectors (CSS1
2763 constraint) allowed</td></tr></tbody></table>
2765 <p>In CSS, selectors express pattern matching rules that determine which style
2766 rules apply to elements in the document tree.
2768 <p>The following selector (CSS level 2) will <b>match</b> all anchors <code>a</code>
2769 with attribute <code>name</code> set inside a section 1 header <code>h1</code>:
2770 <pre>h1 a[name]</pre>
2772 <p>All CSS declarations attached to such a selector are applied to elements
2773 matching it. </div>
2777 <tbody>
2778 <tr>
2780 <tr>
2781 <th>Specification</th>
2782 <td>STTS 3</td>
2783 </tr>
2784 <tr>
2785 <th>Accepts</th>
2786 <td>
2788 <p>type selectors<br>universal selectors<br>attribute selectors<br>class
2789 selectors<br>ID selectors<br>all structural pseudo-classes<br>
2790 all combinators
2792 <p>namespaces</td></tr>
2793 <tr>
2794 <th>Excludes</th>
2795 <td>non-accepted pseudo-classes<br>pseudo-elements<br></td></tr>
2796 <tr>
2797 <th>Extra constraints</th>
2798 <td>some selectors and combinators are not allowed in fragment
2799 descriptions on the right side of STTS declarations.</td></tr></tbody></table>
2800 <form>
2826 </form>
2828 <p>Selectors can be used in STTS 3 in two different
2829 manners:
2830 <ol>
2831 <li>a selection mechanism equivalent to CSS selection mechanism: declarations
2832 attached to a given selector are applied to elements matching that selector,
2833 <li>fragment descriptions that appear on the right side of declarations.
2834 </li></ol></div>
2836 <h2><a name=Conformance></a>13. Conformance and requirements</h2>
2838 <p>This section defines conformance with the present specification only.
2840 <p>The inability of a user agent to implement part of this specification due to
2841 the limitations of a particular device (e.g., non interactive user agents will
2842 probably not implement dynamic pseudo-classes because they make no sense without
2843 interactivity) does not imply non-conformance.
2845 <p>All specifications reusing Selectors must contain a <a
2847 subset of Selectors it accepts or excludes, and describing the constraints
2848 it adds to the current specification.
2850 <p>Invalidity is caused by a parsing error, e.g. an unrecognized token or a token
2851 which is not allowed at the current parsing point.
2853 <p>User agents must observe the rules for handling parsing errors:
2854 <ul>
2855 <li>a simple selector containing an undeclared namespace prefix is invalid</li>
2856 <li>a selector containing an invalid simple selector, an invalid combinator
2857 or an invalid token is invalid. </li>
2858 <li>a group of selectors containing an invalid selector is invalid.</li>
2859 </ul>
2862 errors. (In the case of CSS, the entire rule in which the selector is
2863 used is dropped.)</p>
2865 <!-- Apparently all these references are out of date:
2866 <p>Implementations of this specification must behave as
2868 when parsing selectors and attempting matches. (In particular,
2869 implementations must assume the data is normalized and must not
2870 normalize it.) Normative rules for matching strings are defined in
2873 specification.</p>-->
2875 <h2><a name=Tests></a>14. Tests</h2>
2877 <p>This specification has <a
2879 suite</a> allowing user agents to verify their basic conformance to
2880 the specification. This test suite does not pretend to be exhaustive
2881 and does not cover all possible combined cases of Selectors.</p>
2883 <h2><a name=ACKS></a>15. Acknowledgements</h2>
2885 <p>The CSS working group would like to thank everyone who has sent
2886 comments on this specification over the years.</p>
2888 <p>The working group would like to extend special thanks to Donna
2889 McManus, Justin Baker, Joel Sklar, and Molly Ives Brower who perfermed
2890 the final editorial review.</p>
2892 <h2><a name=references>16. References</a></h2>
2896 <dt>[CSS1]
2897 <dd><a name=refsCSS1></a> Bert Bos, Håkon Wium Lie; "<cite>Cascading Style Sheets, level 1</cite>", W3C Recommendation, 17 Dec 1996, revised 11 Jan 1999
2900 <dt>[CSS21]
2901 <dd><a name=refsCSS21></a> Bert Bos, Tantek Çelik, Ian Hickson, Håkon Wium Lie, editors; "<cite>Cascading Style Sheets, level 2 revision 1</cite>", W3C Working Draft, 13 June 2005
2904 <dt>[CWWW]
2905 <dd><a name=refsCWWW></a> Martin J. Dürst, François Yergeau, Misha Wolf, Asmus Freytag, Tex Texin, editors; "<cite>Character Model for the World Wide Web</cite>", W3C Recommendation, 15 February 2005
2908 <dt>[FLEX]
2909 <dd><a name="refsFLEX"></a> "<cite>Flex: The Lexical Scanner Generator</cite>", Version 2.3.7, ISBN 1882114213
2911 <dt>[HTML4]
2912 <dd><a name="refsHTML4"></a> Dave Ragget, Arnaud Le Hors, Ian Jacobs, editors; "<cite>HTML 4.01 Specification</cite>", W3C Recommendation, 24 December 1999
2915 <dt>[MATH]
2916 <dd><a name="refsMATH"></a> Patrick Ion, Robert Miner, editors; "<cite>Mathematical Markup Language (MathML) 1.01</cite>", W3C Recommendation, revision of 7 July 1999
2917 <dd>(<code><a href="http://www.w3.org/TR/REC-MathML/">http://www.w3.org/TR/REC-MathML/</a></code>)
2919 <dt>[RFC3066]
2920 <dd><a name="refsRFC3066"></a> H. Alvestrand; "<cite>Tags for the Identification of Languages</cite>", Request for Comments 3066, January 2001
2921 <dd>(<a href="http://www.ietf.org/rfc/rfc3066.txt"><code>http://www.ietf.org/rfc/rfc3066.txt</code></a>)
2923 <dt>[STTS]
2924 <dd><a name=refsSTTS></a> Daniel Glazman; "<cite>Simple Tree Transformation Sheets 3</cite>", Electricité de France, submission to the W3C, 11 November 1998
2925 <dd>(<code><a href="http://www.w3.org/TR/NOTE-STTS3">http://www.w3.org/TR/NOTE-STTS3</a></code>)
2927 <dt>[SVG]
2928 <dd><a name="refsSVG"></a> Jon Ferraiolo, 藤沢 淳, Dean Jackson, editors; "<cite>Scalable Vector Graphics (SVG) 1.1 Specification</cite>", W3C Recommendation, 14 January 2003
2931 <dt>[UNICODE]</dt>
2933 href="http://www.unicode.org/versions/Unicode4.1.0/">The Unicode Standard, Version 4.1</a></cite>, The Unicode Consortium. Boston, MA, Addison-Wesley, March 2005. ISBN 0-321-18578-1, as amended by <a href="http://www.unicode.org/versions/Unicode4.0.1/">Unicode 4.0.1</a> and <a href="http://www.unicode.org/versions/Unicode4.1.0/">Unicode 4.1.0</a>.
2934 <dd>(<code><a href="http://www.unicode.org/versions/">http://www.unicode.org/versions/</a></code>)</dd>
2936 <dt>[XML10]
2937 <dd><a name="refsXML10"></a> Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve Maler, François Yergeau, editors; "<cite>Extensible Markup Language (XML) 1.0 (Third Edition)</cite>", W3C Recommendation, 4 February 2004
2940 <dt>[XMLNAMES]
2941 <dd><a name="refsXMLNAMES"></a> Tim Bray, Dave Hollander, Andrew Layman, editors; "<cite>Namespaces in XML</cite>", W3C Recommendation, 14 January 1999
2942 <dd>(<a href="http://www.w3.org/TR/REC-xml-names/"><code>http://www.w3.org/TR/REC-xml-names/</code></a>)
2944 <dt>[YACC]
2945 <dd><a name="refsYACC"></a> S. C. Johnson; "<cite>YACC — Yet another compiler compiler</cite>", Technical Report, Murray Hill, 1975
2947 </dl>
2948 </body>
2949 </html>