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5 <script>
9 // Try to force real results
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111 });
115 });
117 //test("Dojo - div#speech5", function(){
118 //query("div#speech5");
119 //});
121 //test("Dojo - div #speech5", function(){
122 //query("div #speech5");
123 //});
127 });
129 //test("Dojo - div#scene1 div.dialog div", function(){
130 //query("div#scene1 div.dialog div");
131 //});
135 });
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167 </script>
168 </head>
169 <body>
171 <p><a href="http://www.w3.org/"><img height=48 alt=W3C src="http://www.w3.org/Icons/w3c_home" width=72></a>
177 <dl>
179 <dt>This version:
184 <dt>Latest version:
187 http://www.w3.org/TR/css3-selectors</a>
189 <dt>Previous version:
198 <dd class="vcard"><a lang="tr" class="url fn" href="http://www.tantek.com/">Tantek Çelik</a> (Invited Expert)
206 <dd class="vcard"><span class="fn">John Williams</span> (former editor, <span class="company"><a
209 </dl>
220 <a
222 <a
224 <a
226 use</a> rules apply.
230 </div>
235 tree. Selectors have been optimized for use with HTML and XML, and
236 are designed to be usable in performance-critical code.</p>
239 Style Sheets) is a language for describing the rendering of <acronym
242 screen, on paper, in speech, etc. CSS uses Selectors for binding
243 style properties to elements in the document. This document
244 describes extensions to the selectors defined in CSS level 2. These
245 extended selectors will be used by CSS level 3.
251 <p>That is, given an element and a selector, this specification
252 defines whether that element matches the selector.</p>
254 <p>These expressions can also be used, for instance, to select a set
255 of elements, or a single element from a set of elements, by
256 evaluating the expression across all the elements in a
263 <p><em>This section describes the status of this document at the
264 time of its publication. Other documents may supersede this
265 document. A list of current W3C publications and the latest revision
266 of this technical report can be found in the <a
268 http://www.w3.org/TR/.</a></em></p>
276 <p>The CSS Working Group doesn't expect that all implementations of
277 CSS3 will have to implement all selectors. Instead, there will
278 probably be a small number of variants of CSS3, called profiles. For
279 example, it may be that only a profile for interactive user agents
280 will include all of the selectors.</p>
285 document is a revision of the <a
288 implementation feedback received in the past few years. It is
289 expected that this last call will proceed straight to Proposed
290 Recommendation stage since it is believed that interoperability will
291 be demonstrable.</p>
293 <p>All persons are encouraged to review and implement this
294 specification and return comments to the (<a
296 public mailing list <a
299 Members can also send comments directly to the CSS Working
300 Group.
303 <p>This is still a draft document and may be updated, replaced, or
304 obsoleted by other documents at any time. It is inappropriate to
309 The English version of this specification is the only normative
310 version.
318 <ul>
322 </ul>
332 </ul>
334 <ul>
336 </ul>
339 <li class="tocline4"><a href="#attribute-representation">6.3.1. Representation of attributes and attributes values</a>
343 </ul>
353 <ul>
366 </ul>
368 </ul>
369 </li>
370 </ul>
372 <ul>
377 </ul>
384 <li class="tocline4"><a href="#adjacent-sibling-combinators">8.3.1. Adjacent sibling combinator</a>
385 <li class="tocline4"><a href="#general-sibling-combinators">8.3.2. General sibling combinator</a></li>
386 </ul>
387 </li>
388 </ul>
394 </ul>
401 </ul>
403 </div>
409 <p>Some features of this specification are specific to CSS, or have
410 particular limitations or rules specific to CSS. In this
411 specification, these have been described in terms of CSS2.1. <a
416 <p>All of the text of this specification is normative except
417 examples, notes, and sections explicitly marked as
418 non-normative.</p>
424 <p>The main differences between the selectors in CSS2 and those in
425 Selectors are:
427 <ul>
429 <li>the list of basic definitions (selector, group of selectors,
430 simple selector, etc.) has been changed; in particular, what was
431 referred to in CSS2 as a simple selector is now called a sequence
432 of simple selectors, and the term "simple selector" is now used for
433 the components of this sequence</li>
435 <li>an optional namespace component is now allowed in type element
436 selectors, the universal selector and attribute selectors</li>
440 <li>new simple selectors including substring matching attribute
441 selectors, and new pseudo-classes</li>
444 for pseudo-elements</li>
448 <li>profiles to be added to specifications integrating Selectors
449 and defining the set of selectors which is actually supported by
450 each specification</li>
452 <li>Selectors are now a CSS3 Module and an independent
453 specification; other specifications can now refer to this document
454 independently of CSS</li>
458 </ul>
462 <p><em>This section is non-normative, as it merely summarizes the
463 following sections.</em></p>
465 <p>A Selector represents a structure. This structure can be used as a
466 condition (e.g. in a CSS rule) that determines which elements a
467 selector matches in the document tree, or as a flat description of the
468 HTML or XML fragment corresponding to that structure.</p>
470 <p>Selectors may range from simple element names to rich contextual
471 representations.</p>
476 <thead>
477 <tr>
482 <tbody>
483 <tr>
488 selector</a></td>
490 <tr>
496 <tr>
501 selectors</a></td>
503 <tr>
509 selectors</a></td>
511 <tr>
517 selectors</a></td>
519 <tr>
525 selectors</a></td>
527 <tr>
533 selectors</a></td>
535 <tr>
541 selectors</a></td>
543 <tr>
549 selectors</a></td>
551 <tr>
556 pseudo-classes</a></td>
558 <tr>
563 pseudo-classes</a></td>
565 <tr>
568 from the last one</td>
571 pseudo-classes</a></td>
573 <tr>
578 pseudo-classes</a></td>
580 <tr>
583 from the last one</td>
586 pseudo-classes</a></td>
588 <tr>
593 pseudo-classes</a></td>
595 <tr>
600 pseudo-classes</a></td>
602 <tr>
607 pseudo-classes</a></td>
609 <tr>
614 pseudo-classes</a></td>
616 <tr>
621 pseudo-classes</a></td>
623 <tr>
628 pseudo-classes</a></td>
630 <tr>
633 nodes)</td>
636 pseudo-classes</a></td>
638 <tr>
641 which the target is not yet visited (:link) or already visited
642 (:visited)</td>
645 pseudo-classes</a></td>
647 <tr>
652 action pseudo-classes</a></td>
654 <tr>
659 pseudo-class</a></td>
661 <tr>
664 language specifies how language is determined)</td>
667 pseudo-class</a></td>
669 <tr>
672 disabled</td>
675 pseudo-classes</a></td>
677 <tr>
683 pseudo-classes</a></td>
685 <tr>
690 pseudo-element</a></td>
692 <tr>
697 pseudo-element</a></td>
699 <tr>
702 selected/highlighted by the user</td>
705 fragments pseudo-elements</a></td>
707 <tr>
712 pseudo-element</a></td>
714 <tr>
719 pseudo-element</a></td>
721 <tr>
727 selectors</a></td>
729 <tr>
734 selectors</a></td>
736 <tr>
741 pseudo-class</a></td>
743 <tr>
748 combinator</a></td>
750 <tr>
755 combinator</a></td>
757 <tr>
763 <tr>
770 <p>The meaning of each selector is derived from the table above by
772 column.</p>
776 <p>The case sensitivity of document language element names, attribute
777 names, and attribute values in selectors depends on the document
778 language. For example, in HTML, element names are case-insensitive,
779 but in XML, they are case-sensitive.</p>
792 selector or universal selector is allowed in the sequence.</p>
804 sequence of simple selectors.</p>
809 space may appear between a combinator and the simple selectors around
814 never part of white space.</p>
816 <p>The elements of a document tree that are represented by a selector
818 selector consisting of a single sequence of simple selectors
819 represents any element satisfying its requirements. Prepending another
820 sequence of simple selectors and a combinator to a sequence imposes
821 additional matching constraints, so the subjects of a selector are
822 always a subset of the elements represented by the last sequence of
823 simple selectors.</p>
825 <p>An empty selector, containing no sequence of simple selectors and
831 <p>When several selectors share the same declarations, they may be
836 <p>In this example, we condense three rules with identical
837 declarations into one. Thus,</p>
838 <pre>h1 { font-family: sans-serif }
839 h2 { font-family: sans-serif }
840 h3 { font-family: sans-serif }</pre>
843 </div>
846 because all the selectors are valid selectors. If just one of these
847 selectors were invalid, the entire group of selectors would be
848 invalid. This would invalidate the rule for all three heading
849 elements, whereas in the former case only one of the three individual
850 heading rules would be invalidated.</p>
858 element type. A type selector represents an instance of the element
859 type in the document tree.</p>
865 </div>
872 that has been previously declared may be prepended to the element name
876 <p>The namespace component may be left empty to indicate that the
877 selector is only to represent elements with no declared namespace.</p>
879 <p>An asterisk may be used for the namespace prefix, indicating that
880 the selector represents elements in any namespace (including elements
881 with no namespace).</p>
883 <p>Element type selectors that have no namespace component (no
884 namespace separator), represent elements without regard to the
885 element's namespace (equivalent to "<code>*|</code>") unless a default
886 namespace has been declared. If a default namespace has been declared,
887 the selector will represent only elements in the default
888 namespace.</p>
890 <p>A type selector containing a namespace prefix that has not been
892 The mechanism for declaring a namespace prefix is left up to the
893 language implementing Selectors. In CSS, such a mechanism is defined
894 in the General Syntax module.</p>
896 <p>In a namespace-aware client, element type selectors will only match
897 against the <a
899 of the element's <a
902 behaviors in down-level clients.</p>
906 <dl>
910 <dd>elements with name E in any namespace, including those without any
911 declared namespace</dd>
915 <dd>if no default namespace has been specified, this is equivalent to *|E.
916 Otherwise it is equivalent to ns|E where ns is the default namespace.</dd>
917 </dl>
922 <pre>@namespace foo url(http://www.example.com);
923 foo|h1 { color: blue }
924 foo|* { color: yellow }
925 |h1 { color: red }
926 *|h1 { color: green }
927 h1 { color: green }</pre>
932 <p>The second rule will match all elements in the
936 any declared namespace.</p>
939 namespace (including those without any declared namespace).</p>
941 <p>The last rule is equivalent to the fourth rule because no default
942 namespace has been defined.</p>
944 </div>
950 type. It represents any single element in the document tree in any
951 namespace (including those without any declared namespace) if no
952 default namespace has been specified. If a default namespace has been
956 <p>If the universal selector is not the only component of a sequence
961 <ul>
965 </ul>
966 </div>
970 omitted.</p>
974 <p>The universal selector allows an optional namespace component. It
975 is used as follows:</p>
977 <dl>
985 <dd>if no default namespace has been specified, this is equivalent to *|*.
986 Otherwise it is equivalent to ns|* where ns is the default namespace.</dd>
987 </dl>
989 <p>A universal selector containing a namespace prefix that has not
991 selector. The mechanism for declaring a namespace prefix is left up
992 to the language implementing Selectors. In CSS, such a mechanism is
993 defined in the General Syntax module.</p>
998 <p>Selectors allow the representation of an element's attributes. When
999 a selector is used as an expression to match against an element,
1000 attribute selectors must be considered to match an element if that
1001 element has an attribute that matches the attribute represented by the
1002 attribute selector.</p>
1005 selectors</a></h4>
1009 <dl>
1012 the attribute.</dd>
1021 spaces).</dd>
1031 </dl>
1033 <p>Attribute values must be identifiers or strings. The
1034 case-sensitivity of attribute names and values in selectors depends on
1035 the document language.</p>
1043 value:</p>
1047 <p>In the following example, the selector represents a
1053 <p>Multiple attribute selectors can be used to represent several
1054 attributes of an element, or several conditions on the same
1063 and "~=". The first selector will represent, for example, the value
1083 <p>Similarly, the following selectors represents a
1087 <pre>DIALOGUE[character=romeo]
1088 DIALOGUE[character=juliet]</pre>
1090 </div>
1093 selectors</h4>
1095 <p>Three additional attribute selectors are provided for matching
1096 substrings in the value of an attribute:</p>
1098 <dl>
1108 </dl>
1110 <p>Attribute values must be identifiers or strings. The
1111 case-sensitivity of attribute names in selectors depends on the
1112 document language.</p>
1117 image:</p>
1125 </div>
1129 <p>Attribute selectors allow an optional namespace component to the
1130 attribute name. A namespace prefix that has been previously declared
1131 may be prepended to the attribute name separated by the namespace
1133 the Namespaces in the XML recommendation, default namespaces do not
1134 apply to attributes, therefore attribute selectors without a namespace
1135 component apply only to attributes that have no declared namespace
1136 (equivalent to "<code>|attr</code>"). An asterisk may be used for the
1137 namespace prefix indicating that the selector is to match all
1138 attribute names without regard to the attribute's namespace.
1140 <p>An attribute selector with an attribute name containing a namespace
1141 prefix that has not been previously declared is an <a
1143 a namespace prefix is left up to the language implementing Selectors.
1144 In CSS, such a mechanism is defined in the General Syntax module.
1149 [foo|att=val] { color: blue }
1150 [*|att] { color: yellow }
1151 [|att] { color: green }
1152 [att] { color: green }</pre>
1154 <p>The first rule will match only elements with the attribute
1158 <p>The second rule will match only elements with the attribute
1160 (including no declared namespace).</p>
1162 <p>The last two rules are equivalent and will match only elements
1164 declared to be in a namespace.</p>
1166 </div>
1170 <p>Attribute selectors represent explicitly set attribute values in
1171 the document tree. Default attribute values may be defined in a DTD or
1172 elsewhere, but cannot always be selected by attribute
1173 selectors. Selectors should be designed so that they work even if the
1174 default values are not included in the document tree.</p>
1183 knowledge of that namespace to treat default attribute values as if
1184 they were present in the document. (For example, an XHTML UA is not
1185 required to use its built-in knowledge of the XHTML DTD.)</p>
1188 choose to ignore external subsets.</p>
1200 <pre>EXAMPLE[notation=decimal] { /*... default property settings ...*/ }
1201 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre>
1204 is set by default, i.e. not set explicitly. To catch all cases, the
1205 attribute selector for the default value must be dropped:</p>
1207 <pre>EXAMPLE { /*... default property settings ...*/ }
1208 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre>
1211 more specific than the tag
1212 selector alone, the style declarations in the second rule will override
1213 those in the first for elements that have a "notation" attribute value
1214 of "octal". Care has to be taken that all property declarations that
1215 are to apply only to the default case are overridden in the non-default
1216 cases' style rules.</p>
1218 </div>
1226 the same meaning. The attribute value must immediately follow the
1229 <p>UAs may apply selectors using the period (.) notation in XML
1230 documents if the UA has namespace-specific knowledge that allows it to
1232 respective namespace. One such example of namespace-specific knowledge
1233 is the prose in the specification for a particular namespace (e.g. SVG
1244 <p>We can assign style information to all elements with
1253 <p>The following assigns style only to H1 elements with
1258 <p>Given these rules, the first H1 instance below would not have
1259 green text, while the second would:</p>
1264 </div>
1274 has been assigned a list of <a
1284 </div>
1287 power to the "class" attribute, authors could conceivably design their
1288 own "document language" based on elements with almost no associated
1289 presentation (such as DIV and SPAN in HTML) and assigning style
1290 information through the "class" attribute. Authors should avoid this
1291 practice since the structural elements of a document language often
1292 have recognized and accepted meanings and author-defined classes may
1293 not.</p>
1296 class attributes, their values must be concatenated with spaces
1297 between the values before searching for the class. As of this time the
1298 working group is not aware of any manner in which this situation can
1299 be reached, however, so this behavior is explicitly non-normative in
1300 this specification.</p>
1304 <p>Document languages may contain attributes that are declared to be
1305 of type ID. What makes attributes of type ID special is that no two
1306 such attributes can have the same value in a document, regardless of
1307 the type of the elements that carry them; whatever the document
1308 language, an ID typed attribute can be used to uniquely identify its
1309 element. In HTML all ID attributes are named "id"; XML applications
1310 may name ID attributes differently, but the same restriction
1311 applies.</p>
1313 <p>An ID-typed attribute of a document language allows authors to
1314 assign an identifier to one element instance in the document tree. W3C
1315 ID selectors represent an element instance based on its identifier. An
1318 identifier.</p>
1320 <p>Selectors does not specify how a UA knows the ID-typed attribute of
1321 an element. The UA may, e.g., read a document's DTD, have the
1322 information hard-coded or ask the user.
1329 <p>The following ID selector represents any element whose ID-typed
1332 <p>The following selector represents any element whose ID-typed
1335 </div>
1339 contains an element's IDs is contained in a DTD or a schema. When
1340 parsing XML, UAs do not always read the DTD, and thus may not know
1341 what the ID of an element is (though a UA may have namespace-specific
1342 knowledge that allows it to determine which attribute is the ID
1343 attribute for that namespace). If a style sheet designer knows or
1344 suspects that a UA may not know what the ID of an element is, he
1345 should use normal attribute selectors instead:
1349 <p>If an element has multiple ID attributes, all of them must be
1350 treated as IDs for that element for the purposes of the ID
1351 selector. Such a situation could be reached using mixtures of xml:id,
1352 DOM3 Core, XML DTDs, and namespace-specific knowledge.</p>
1356 <p>The pseudo-class concept is introduced to permit selection based on
1357 information that lies outside of the document tree or that cannot be
1358 expressed using the other simple selectors.</p>
1362 optionally by a value between parentheses.</p>
1364 <p>Pseudo-classes are allowed in all sequences of simple selectors
1365 contained in a selector. Pseudo-classes are allowed anywhere in
1366 sequences of simple selectors, after the leading type selector or
1367 universal selector (possibly omitted). Pseudo-class names are
1368 case-insensitive. Some pseudo-classes are mutually exclusive, while
1369 others can be applied simultaneously to the same
1370 element. Pseudo-classes may be dynamic, in the sense that an element
1371 may acquire or lose a pseudo-class while a user interacts with the
1372 document.</p>
1377 <p>Dynamic pseudo-classes classify elements on characteristics other
1378 than their name, attributes, or content, in principle characteristics
1379 that cannot be deduced from the document tree.</p>
1381 <p>Dynamic pseudo-classes do not appear in the document source or
1382 document tree.</p>
1387 <p>User agents commonly display unvisited links differently from
1388 previously visited ones. Selectors
1392 <ul>
1394 not yet been visited.</li>
1396 been visited by the user. </li>
1397 </ul>
1399 <p>After some amount of time, user agents may choose to return a
1400 visited link to the (unvisited) ':link' state.</p>
1408 <p>The following selector represents links carrying class
1413 </div>
1416 authors to abuse the :link and :visited pseudo-classes to determine
1417 which sites a user has visited without the user's consent.
1419 <p>UAs may therefore treat all links as unvisited links, or implement
1420 other measures to preserve the user's privacy while rendering visited
1421 and unvisited links differently.</p>
1424 :hover, :active, and :focus</a></h5>
1426 <p>Interactive user agents sometimes change the rendering in response
1427 to user actions. Selectors provides
1428 three pseudo-classes for the selection of an element the user is
1429 acting on.</p>
1431 <ul>
1434 designates an element with a pointing device, but does not activate
1435 it. For example, a visual user agent could apply this pseudo-class
1436 when the cursor (mouse pointer) hovers over a box generated by the
1437 element. User agents not that do not support <a
1439 media</a> do not have to support this pseudo-class. Some conforming
1440 user agents that support <a
1442 media</a> may not be able to support this pseudo-class (e.g., a pen
1443 device that does not detect hovering).</li>
1446 is being activated by the user. For example, between the times the
1447 user presses the mouse button and releases it.</li>
1450 has the focus (accepts keyboard or mouse events, or other forms of
1451 input). </li>
1453 </ul>
1455 <p>There may be document language or implementation specific limits on
1459 <p>These pseudo-classes are not mutually exclusive. An element may
1460 match several pseudo-classes at the same time.</p>
1462 <p>Selectors doesn't define if the parent of an element that is
1463 ':active' or ':hover' is also in that state.</p>
1467 <pre>a:link /* unvisited links */
1468 a:visited /* visited links */
1469 a:hover /* user hovers */
1470 a:active /* active links */</pre>
1472 <pre>a:focus
1473 a:focus:hover</pre>
1475 the pseudo-class :focus and in the pseudo-class :hover.</p>
1476 </div>
1479 and ':active' (or ':link' and ':active').</p>
1483 <p>Some URIs refer to a location within a resource. This kind of URI
1485 identifier (called the fragment identifier).</p>
1487 <p>URIs with fragment identifiers link to a certain element within the
1488 document, known as the target element. For instance, here is a URI
1490 document:</p>
1495 pseudo-class. If the document's URI has no fragment identifier, then
1496 the document has no target element.</p>
1503 URI.</p>
1504 </div>
1509 target element red and place an image before it, if there is one:</p>
1510 <pre>*:target { color : red }
1511 *:target::before { content : url(target.png) }</pre>
1512 </div>
1516 <p>If the document language specifies how the human language of an
1517 element is determined, it is possible to write selectors that
1518 represent an element based on its language. For example, in HTML <a
1521 element, and possibly by information from the protocol (such as HTTP
1523 there may be other document language-specific methods for determining
1524 the language.</p>
1527 is in language C. Whether an element is represented by a
1529 being either equal to, or a hyphen-separated substring of, the
1530 element's language value, in the same way as if performed by the <a
1532 selectors. The identifier C does not have to be a valid language
1533 name.</p>
1547 <p>The two following selectors represent an HTML document that is in
1548 Belgian, French, or German. The two next selectors represent
1550 or German.</p>
1551 <pre>html:lang(fr-be)
1552 html:lang(de)
1553 :lang(fr-be) > q
1555 </div>
1562 the look of user interface elements that are enabled — which the
1563 user can select or activate in some fashion (e.g. clicking on a button
1564 with a mouse). There is a need for such a pseudo-class because there
1565 is no way to programmatically specify the default appearance of say,
1567 would look like when it was disabled.</p>
1570 author to specify precisely how a disabled or inactive user interface
1571 element should look.</p>
1573 <p>Most elements will be neither enabled nor disabled. An element is
1574 enabled if the user can either activate it or transfer the focus to
1575 it. An element is disabled if it could be enabled, but the user cannot
1576 presently activate it or transfer focus to it.</p>
1581 <p>Radio and checkbox elements can be toggled by the user. Some menu
1582 items are "checked" when the user selects them. When such elements are
1586 attributes as described in <a
1591 in nature, and is altered by user action, since it can also be based
1600 <p>Radio and checkbox elements can be toggled by the user, but are
1601 sometimes in an indeterminate state, neither checked nor unchecked.
1602 This can be due to an element attribute, or DOM manipulation.</p>
1604 <p>A future version of this specification may introduce an
1606 <!--While the <code>:indeterminate</code> pseudo-class is dynamic in
1607 nature, and is altered by user action, since it can also be based on
1608 the presence of an element attribute, it applies to all media.</p>
1610 <p>Components of a radio-group initialized with no pre-selected choice
1613 </div>
1619 pseudo-classes</dfn> to permit selection based on extra information that lies in
1620 the document tree but cannot be represented by other simple selectors or
1621 combinators.
1623 <p>Note that standalone pieces of PCDATA (text nodes in the DOM) are
1624 not counted when calculating the position of an element in the list of
1625 children of its parent. When calculating the position of an element in
1626 the list of children of its parent, the index numbering starts at 1.
1632 the root of the document. In HTML 4, this is always the
1638 <p>The
1640 pseudo-class notation represents an element that has
1646 each. For example, this allows the selectors to address every other
1647 row in a table, and could be used to alternate the color
1650 integers. The index of the first child of an element is 1.
1661 tr:nth-child(odd) /* same */
1662 tr:nth-child(2n) /* represents every even row of an HTML table */
1663 tr:nth-child(even) /* same */
1665 /* Alternate paragraph colours in CSS */
1670 </div>
1675 included, so the syntax simplifies to
1683 </div>
1691 bar:nth-child(n+0) /* same */
1692 bar:nth-child(n) /* same */
1694 </div>
1703 </div>
1706 pseudo-class represents no element in the document tree.</p>
1711 tree.</p>
1716 </div>
1719 expression must be removed (it is effectively replaced by the "-"
1727 </div>
1733 pseudo-class notation represents an element that has
1739 as arguments.
1746 foo:nth-last-child(odd) /* represents all odd foo elements in their parent element,
1747 counting from the last one */</pre>
1748 </div>
1754 pseudo-class notation represents an element that has
1759 of that type after all the children of that type have been split into
1761 for the syntax of its argument. It also accepts the
1770 </div>
1776 pseudo-class notation represents an element that has
1788 following selector:</p>
1791 selector ends up being just as long:</p>
1793 </div>
1799 represents an element that is the first child of some other element.
1813 fragment:
1821 a:first-child /* Same (assuming a is not the root element) */</pre>
1822 </div>
1827 represents an element that is the last child of some other element.
1834 </div>
1839 represents an element that is the first sibling of its type in the list of
1840 children of its parent element.
1844 <p>The following selector represents a definition title
1847 its parent element.</p>
1850 elements in the following example but not for the third one:</p>
1862 </div>
1868 the last sibling of its type in the list of children of its parent
1869 element.</p>
1873 <p>The following selector represents the last data cell
1876 </div>
1880 <p>Represents an element that has a parent element and whose parent
1881 element has no other element children. Same as
1884 specificity.</p>
1888 <p>Represents an element that has a parent element and whose parent
1889 element has no other element children with the same element name. Same
1892 specificity.</p>
1898 no children at all. In terms of the DOM, only element nodes and text
1899 nodes (including CDATA nodes and entity references) whose data has a
1900 non-zero length must be considered as affecting emptiness; comments,
1901 PIs, and other nodes must not affect whether an element is considered
1902 empty or not.</p>
1909 following fragments:</p>
1913 </div>
1915 <h4><a name=content-selectors>6.6.6. Blank</a></h4> <!-- It's the Return of Appendix H!!! Run away! -->
1918 <!-- (used to be :contains()) -->
1924 selector</a> (excluding the negation pseudo-class itself and
1925 pseudo-elements) as an argument. It represents an element that is not
1926 represented by the argument.
1928 <!-- pseudo-elements are not simple selectors, so the above paragraph
1929 may be a bit confusing -->
1934 elements in an HTML document that are not disabled.</p>
1937 elements.</p>
1939 <p>The following group of selectors represents all HTML elements
1940 except links.</p>
1942 </div>
1944 <p>Default namespace declarations do not affect the argument of the
1945 negation pseudo-class unless the argument is a universal selector or a
1946 type selector.</p>
1950 <p>Assuming that the default namespace is bound to
1951 "http://example.com/", the following selector represents all
1952 elements that are not in that namespace:</p>
1954 <p>The following CSS selector matches any element being hovered,
1955 regardless of its namespace. In particular, it is not limited to
1956 only matching elements in the default namespace that are not being
1957 hovered, and elements not in the default namespace don't match the
1960 </div>
1966 specificity.</p>
1970 <p>Pseudo-elements create abstractions about the document tree beyond
1971 those specified by the document language. For instance, document
1972 languages do not offer mechanisms to access the first letter or first
1973 line of an element's content. Pseudo-elements allow designers to refer
1974 to this otherwise inaccessible information. Pseudo-elements may also
1975 provide designers a way to refer to content that does not exist in the
1978 content).</p>
1981 by the name of the pseudo-element.</p>
1984 in order to establish a discrimination between pseudo-classes and
1985 pseudo-elements. For compatibility with existing style sheets, user
1986 agents must also accept the previous one-colon notation for
1992 <p>Only one pseudo-element may appear per selector, and if present it
1993 must appear after the sequence of simple selectors that represents the
1995 future version of this specification may allow multiple
1996 pesudo-elements per selector.</span></p>
2001 of the first formatted line of an element.
2008 </div>
2011 HTML element. It does match a pseudo-element that conforming user
2012 agents will insert at the beginning of every paragraph.</p>
2014 <p>Note that the length of the first line depends on a number of
2015 factors, including the width of the page, the font size, etc. Thus,
2016 an ordinary HTML paragraph such as:</p>
2018 <pre>
2020 paragraph that will be broken into several
2021 lines. The first line will be identified
2022 by a fictional tag sequence. The other lines
2023 will be treated as ordinary lines in the
2025 </pre>
2027 <p>the lines of which happen to be broken as follows:
2029 <pre>
2030 THIS IS A SOMEWHAT LONG HTML PARAGRAPH THAT
2031 will be broken into several lines. The first
2032 line will be identified by a fictional tag
2033 sequence. The other lines will be treated as
2034 ordinary lines in the paragraph.
2035 </pre>
2039 fictional tag sequence helps to show how properties are inherited.</p>
2041 <pre>
2044 lines. The first line will be identified
2045 by a fictional tag sequence. The other lines
2046 will be treated as ordinary lines in the
2048 </pre>
2050 <p>If a pseudo-element breaks up a real element, the desired effect
2051 can often be described by a fictional tag sequence that closes and
2052 then re-opens the element. Thus, if we mark up the previous paragraph
2055 <pre>
2057 paragraph that will be broken into several
2059 by a fictional tag sequence. The other lines
2060 will be treated as ordinary lines in the
2062 </pre>
2064 <p>the user agent could simulate start and end tags for
2068 <pre>
2070 somewhat long HTML
2071 paragraph that will <b></SPAN></b></P::first-line><b><SPAN class="test"></b> be
2072 broken into several
2074 by a fictional tag sequence. The other lines
2075 will be treated as ordinary lines in the
2077 </pre>
2080 attached to a block-level element, an inline-block, a table-caption,
2081 or a table-cell.</p>
2084 element may occur inside a
2085 block-level descendant in the same flow (i.e., a block-level
2086 descendant that is not positioned and not a float). E.g., the first
2091 <p>The first line of a table-cell or inline-block cannot be the first
2102 <p>A UA should act as if the fictional start tags of the
2104 innermost enclosing block-level element. (Since CSS1 and CSS2 were
2105 silent on this case, authors should not rely on this behavior.) Here
2106 is an example. The fictional tag sequence for</p>
2108 <pre>
2113 </pre>
2117 <pre>
2119 <P><DIV::first-line><P::first-line>First paragraph</P::first-line></DIV::first-line></P>
2122 </pre>
2125 inline-level element, but with certain restrictions. In CSS, the
2127 pseudo-element: font properties, color property, background
2128 properties, 'word-spacing', 'letter-spacing', 'text-decoration',
2129 'vertical-align', 'text-transform', 'line-height'. UAs may apply other
2130 properties as well.</p>
2136 letter of the first line of a block, if it is not preceded by any
2137 other content (such as images or inline tables) on its line. The
2139 caps", which are common typographical effects. This type of initial
2140 letter is similar to an inline-level element if its 'float' property
2141 is 'none'; otherwise, it is similar to a floated element.</p>
2144 pseudo-elements: font properties, 'text-decoration', 'text-transform',
2145 'letter-spacing', 'word-spacing' (when appropriate), 'line-height',
2146 'float', 'vertical-align' (only if 'float' is 'none'), margin
2147 properties, padding properties, border properties, color property,
2148 background properties. UAs may apply other properties as well. To
2149 allow UAs to render a typographically correct drop cap or initial cap,
2150 the UA may choose a line-height, width and height based on the shape
2151 of the letter, unlike for normal elements.</p>
2155 <p>This example shows a possible rendering of an initial cap. Note
2157 pseudo-element is 1.1, but the UA in this example has computed the
2158 height of the first letter differently, so that it doesn't cause any
2159 unnecessary space between the first two lines. Also note that the
2162 <pre>
2163 p { line-height: 1.1 }
2164 p::first-letter { font-size: 3em; font-weight: normal }
2165 span { font-weight: bold }
2166 ...
2170 En dagelix geschrey de bange stad ontzet.
2171 </pre>
2174 </div>
2175 </div>
2180 <pre>
2187 P::first-letter { font-size: 200%; font-weight: bold; float: left }
2188 SPAN { text-transform: uppercase }
2196 </pre>
2201 <P><img src="first-letter.gif" alt="Image illustrating the combined effect of the ::first-letter and ::first-line pseudo-elements"></p>
2202 </div>
2207 <pre>
2211 T
2214 few words of an article in the Economist.
2216 </pre>
2219 the content (i.e., the initial character), while the ::first-line
2220 pseudo-element start tag is inserted right after the start tag of the
2221 block element.</p> </div>
2223 <p>In order to achieve traditional drop caps formatting, user agents
2224 may approximate font sizes, for example to align baselines. Also, the
2225 glyph outline may be taken into account when formatting.</p>
2229 punctuation classes), that precedes or follows the first letter should
2235 </div>
2242 block, list-item, table-cell, table-caption, and inline-block
2244 may allow this pesudo-element to apply to more element
2245 types.</span></p>
2248 such elements that contain text, or that have a descendant in the same
2249 flow that contains text. A UA should act as if the fictional start tag
2250 of the ::first-letter pseudo-element is just before the first text of
2251 the element, even if that first text is in a descendant.</p>
2255 <p>The fictional tag sequence for this HTMLfragment:
2258 <p>is:
2261 </div>
2263 <p>The first letter of a table-cell or inline-block cannot be the
2276 <p>In CSS, if an element is a list item ('display: list-item'), the
2278 principal box after the marker. UAs may ignore
2288 </div>
2290 <p>Some languages may have specific rules about how to treat certain
2291 letter combinations. In Dutch, for example, if the letter combination
2292 "ij" appears at the beginning of a word, both letters should be
2295 <p>If the letters that would form the ::first-letter are not in the
2297 may create a ::first-letter pseudo-element from one of the elements,
2298 both elements, or simply not create a pseudo-element.</p>
2300 <p>Similarly, if the first letter(s) of the block are not at the start
2301 of the line (for example due to bidirectional reordering), then the UA
2302 need not create the pseudo-element(s).
2307 how overlapping pseudo-elements may interact. The first letter of
2308 each P element will be green with a font size of '24pt'. The rest of
2309 the first formatted line will be 'blue' while the rest of the
2310 paragraph will be 'red'.</p>
2313 p::first-letter { color: green; font-size: 200% }
2314 p::first-line { color: blue }
2325 S
2328 ends up on two lines
2335 </div>
2341 of a document that has been highlighted by the user. This also
2342 applies, for example, to selected text within an editable text
2343 field. This pseudo-element should not be confused with the <code><a
2348 nature, and is altered by user action, it is reasonable to expect that
2349 when a UA re-renders to a static medium (such as a printed page, see
2351 dynamic medium (like screen), the UA may wish to transfer the current
2353 appropriate formatting and rendering take effect as well. This is not
2355 pseudo-element for static media.
2358 pseudo-elements: color, background, cursor (optional), outline
2359 (optional). The computed value of the 'background-image' property on
2366 can be used to describe generated content before or after an element's
2373 element including the inserted text.</p>
2379 <p>At times, authors may want selectors to describe an element that is
2380 the descendant of another element in the document tree (e.g., "an
2381 <code>EM</code> element that is contained within an <code>H1</code>
2382 element"). Descendant combinators express such a relationship. A
2384 separates two sequences of simple selectors. A selector of the form
2394 description of the following fragment:</p>
2401 either side of the "*" is not part of the universal selector; the
2402 whitespace is a combinator indicating that the DIV must be the
2403 ancestor of some element, and that that element must be an ancestor
2404 of the P.</p>
2405 <p>The following selector, which combines descendant combinators and
2410 </div>
2415 between two elements. A child combinator is made of the
2417 separates two sequences of simple selectors.
2425 <p>The following example combines descendant combinators and child
2426 combinators.</p>
2433 </div>
2435 <p>For information on selecting the first child of an element, please
2436 see the section on the <code><a
2438 above.</p>
2442 <p>There are two different sibling combinators: the adjacent sibling
2443 combinator and the general sibling combinator. In both cases,
2444 non-element nodes (e.g. text between elements) are ignored when
2445 considering adjacency of elements.</p>
2451 sequences of simple selectors. The elements represented by the two
2452 sequences share the same parent in the document tree and the element
2453 represented by the first sequence immediately precedes the element
2454 represented by the second one.</p>
2461 <p>The following selector is conceptually similar to the one in the
2462 previous example, except that it adds an attribute selector — it
2466 </div>
2473 simple selectors. The elements represented by the two sequences share
2474 the same parent in the document tree and the element represented by
2475 the first sequence precedes (not necessarily immediately) the element
2476 represented by the second one.</p>
2482 is a correct and valid, but partial, description of:</p>
2486 </div>
2492 <ul>
2494 <li>count the number of class selectors, attributes selectors, and pseudo-classes in the selector (= b)</li>
2497 </ul>
2500 are counted like any other, but the negation itself does not count as
2501 a pseudo-class.</p>
2503 <p>Concatenating the three numbers a-b-c (in a number system with a
2504 large base) gives the specificity.</p>
2517 </pre>
2518 </div>
2528 <p>The grammar below defines the syntax of Selectors. It is globally
2530 it directly, since it doesn't express the parsing conventions). The
2531 format of the productions is optimized for human consumption and some
2533 are used:</p>
2535 <ul>
2541 </ul>
2545 <pre>selectors_group
2546 : selector [ COMMA S* selector ]*
2547 ;
2549 selector
2550 : simple_selector_sequence [ combinator simple_selector_sequence ]*
2551 ;
2553 combinator
2554 /* combinators can be surrounded by white space */
2555 : PLUS S* | GREATER S* | TILDE S* | S+
2556 ;
2558 simple_selector_sequence
2559 : [ type_selector | universal ]
2560 [ HASH | class | attrib | pseudo | negation ]*
2561 | [ HASH | class | attrib | pseudo | negation ]+
2562 ;
2564 type_selector
2565 : [ namespace_prefix ]? element_name
2566 ;
2568 namespace_prefix
2569 : [ IDENT | '*' ]? '|'
2570 ;
2572 element_name
2573 : IDENT
2574 ;
2576 universal
2577 : [ namespace_prefix ]? '*'
2578 ;
2580 class
2581 : '.' IDENT
2582 ;
2584 attrib
2585 : '[' S* [ namespace_prefix ]? IDENT S*
2586 [ [ PREFIXMATCH |
2587 SUFFIXMATCH |
2588 SUBSTRINGMATCH |
2589 '=' |
2590 INCLUDES |
2591 DASHMATCH ] S* [ IDENT | STRING ] S*
2592 ]? ']'
2593 ;
2595 pseudo
2596 /* '::' starts a pseudo-element, ':' a pseudo-class */
2597 /* Exceptions: :first-line, :first-letter, :before and :after. */
2598 /* Note that pseudo-elements are restricted to one per selector and */
2599 /* occur only in the last simple_selector_sequence. */
2600 : ':' ':'? [ IDENT | functional_pseudo ]
2601 ;
2603 functional_pseudo
2604 : FUNCTION S* expression ')'
2605 ;
2607 expression
2608 /* In CSS3, the expressions are identifiers, strings, */
2609 /* or of the form "an+b" */
2610 : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
2611 ;
2613 negation
2614 : NOT S* negation_arg S* ')'
2615 ;
2617 negation_arg
2618 : type_selector | universal | HASH | class | attrib | pseudo
2619 ;</pre>
2626 case-insensitive.</p>
2629 number that current versions of Flex can deal with (decimal 255). They
2634 <pre>%option case-insensitive
2636 ident [-]?{nmstart}{nmchar}*
2637 name {nmchar}+
2638 nmstart [_a-z]|{nonascii}|{escape}
2641 escape {unicode}|\\[^\n\r\f0-9a-f]
2642 nmchar [_a-z0-9-]|{nonascii}|{escape}
2644 string {string1}|{string2}
2646 string2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\'
2647 invalid {invalid1}|{invalid2}
2649 invalid2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*
2650 nl \n|\r\n|\r|\f
2651 w [ \t\r\n\f]*
2653 %%
2655 [ \t\r\n\f]+ return S;
2662 {ident} return IDENT;
2663 {string} return STRING;
2665 {num} return NUMBER;
2672 @{ident} return ATKEYWORD;
2673 {invalid} return INVALID;
2674 {num}% return PERCENTAGE;
2675 {num}{ident} return DIMENSION;
2681 U\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})? return UNICODE_RANGE;
2683 \/\*[^*]*\*+([^/*][^*]*\*+)*\/ /* ignore comments */
2685 . return *yytext;</pre>
2689 <h2><a name=downlevel>11. Namespaces and down-level clients</a></h2>
2691 <p>An important issue is the interaction of CSS selectors with XML
2692 documents in web clients that were produced prior to this
2693 document. Unfortunately, due to the fact that namespaces must be
2694 matched based on the URI which identifies the namespace, not the
2695 namespace prefix, some mechanism is required to identify namespaces in
2696 CSS by their URI as well. Without such a mechanism, it is impossible
2697 to construct a CSS style sheet which will properly match selectors in
2698 all cases against a random set of XML documents. However, given
2699 complete knowledge of the XML document to which a style sheet is to be
2700 applied, and a limited use of namespaces within the XML document, it
2701 is possible to construct a style sheet in which selectors would match
2702 elements and attributes correctly.</p>
2704 <p>It should be noted that a down-level CSS client will (if it
2705 properly conforms to CSS forward compatible parsing rules) ignore all
2706 <code>@namespace</code> at-rules, as well as all style rules that make
2707 use of namespace qualified element type or attribute selectors. The
2708 syntax of delimiting namespace prefixes in CSS was deliberately chosen
2709 so that down-level CSS clients would ignore the style rules rather
2710 than possibly match them incorrectly.</p>
2712 <p>The use of default namespaces in CSS makes it possible to write
2713 element type selectors that will function in both namespace aware CSS
2714 clients as well as down-level clients. It should be noted that
2715 down-level clients may incorrectly match selectors against XML
2716 elements in other namespaces.</p>
2718 <p>The following are scenarios and examples in which it is possible to
2719 construct style sheets which would function properly in web clients
2720 that do not implement this proposal.</p>
2722 <ol>
2723 <li>
2725 <p>The XML document does not use namespaces.</p>
2727 <ul>
2729 <li>In this case, it is obviously not necessary to declare or use
2730 namespaces in the style sheet. Standard CSS element type and
2731 attribute selectors will function adequately in a down-level
2732 client.</li>
2734 <li>In a CSS namespace aware client, the default behavior of
2735 element selectors matching without regard to namespace will
2736 function properly against all elements, since no namespaces are
2737 present. However, the use of specific element type selectors that
2739 will guarantee that selectors will match only XML elements that do
2740 not have a declared namespace. </li>
2742 </ul>
2744 </li>
2746 <li>
2748 <p>The XML document defines a single, default namespace used
2749 throughout the document. No namespace prefixes are used in element
2750 names.</p>
2752 <ul>
2754 <li>In this case, a down-level client will function as if
2755 namespaces were not used in the XML document at all. Standard CSS
2756 element type and attribute selectors will match against all
2757 elements. </li>
2759 </ul>
2761 </li>
2763 <li>
2765 <p>The XML document does <b>not</b> use a default namespace, all
2766 namespace prefixes used are known to the style sheet author, and
2767 there is a direct mapping between namespace prefixes and namespace
2768 URIs. (A given prefix may only be mapped to one namespace URI
2769 throughout the XML document; there may be multiple prefixes mapped
2770 to the same URI).</p>
2772 <ul>
2774 <li>In this case, the down-level client will view and match
2775 element type and attribute selectors based on their fully
2776 qualified name, not the local part as outlined in the <a
2779 to describe the fully qualified names, e.g.
2781 <code><html:h1></code>. Selectors using the qualified name
2782 will only match XML elements that use the same prefix. Other
2783 namespace prefixes used in the XML that are mapped to the same URI
2784 will not match as expected unless additional CSS style rules are
2785 declared for them.</li>
2787 <li>Note that selectors declared in this fashion will
2788 <em>only</em> match in down-level clients. A CSS namespace aware
2789 client will match element type and attribute selectors based on
2790 the name's local part. Selectors declared with the fully
2791 qualified name will not match (unless there is no namespace prefix
2792 in the fully qualified name).</li>
2794 </ul>
2796 </li>
2798 </ol>
2800 <p>In other scenarios: when the namespace prefixes used in the XML are
2801 not known in advance by the style sheet author; or a combination of
2802 elements with no namespace are used in conjunction with elements using
2803 a default namespace; or the same namespace prefix is mapped to
2804 <em>different</em> namespace URIs within the same document, or in
2805 different documents; it is impossible to construct a CSS style sheet
2806 that will function properly against all elements in those documents,
2807 unless, the style sheet is written using a namespace URI syntax (as
2808 outlined in this document or similar) and the document is processed by
2809 a CSS and XML namespace aware client.</p>
2811 <h2><a name=profiling>12. Profiles</a></h2>
2813 <p>Each specification using Selectors must define the subset of W3C
2814 Selectors it allows and excludes, and describe the local meaning of
2815 all the components of that subset.</p>
2817 <p>Non normative examples:
2821 <tbody>
2822 <tr>
2824 <tr>
2825 <th>Specification</th>
2826 <td>CSS level 1</td></tr>
2827 <tr>
2828 <th>Accepts</th>
2829 <td>type selectors<br>class selectors<br>ID selectors<br>:link,
2830 :visited and :active pseudo-classes<br>descendant combinator
2831 <br>::first-line and ::first-letter pseudo-elements</td></tr>
2832 <tr>
2833 <th>Excludes</th>
2834 <td>
2836 <p>universal selector<br>attribute selectors<br>:hover and :focus
2837 pseudo-classes<br>:target pseudo-class<br>:lang() pseudo-class<br>all UI
2838 element states pseudo-classes<br>all structural
2839 pseudo-classes<br>negation pseudo-class<br>all
2840 UI element fragments pseudo-elements<br>::before and ::after
2841 pseudo-elements<br>child combinators<br>sibling combinators
2843 <p>namespaces</td></tr>
2844 <tr>
2845 <th>Extra constraints</th>
2846 <td>only one class selector allowed per sequence of simple
2847 selectors</td></tr></tbody></table><br><br>
2849 <tbody>
2850 <tr>
2852 <tr>
2853 <th>Specification</th>
2854 <td>CSS level 2</td></tr>
2855 <tr>
2856 <th>Accepts</th>
2857 <td>type selectors<br>universal selector<br>attribute presence and
2858 values selectors<br>class selectors<br>ID selectors<br>:link, :visited,
2859 :active, :hover, :focus, :lang() and :first-child pseudo-classes
2860 <br>descendant combinator<br>child combinator<br>adjacent sibling
2861 combinator<br>::first-line and ::first-letter pseudo-elements<br>::before
2862 and ::after pseudo-elements</td></tr>
2863 <tr>
2864 <th>Excludes</th>
2865 <td>
2867 <p>content selectors<br>substring matching attribute
2868 selectors<br>:target pseudo-classes<br>all UI element
2869 states pseudo-classes<br>all structural pseudo-classes other
2870 than :first-child<br>negation pseudo-class<br>all UI element
2871 fragments pseudo-elements<br>general sibling combinators
2873 <p>namespaces</td></tr>
2874 <tr>
2875 <th>Extra constraints</th>
2876 <td>more than one class selector per sequence of simple selectors (CSS1
2877 constraint) allowed</td></tr></tbody></table>
2879 <p>In CSS, selectors express pattern matching rules that determine which style
2880 rules apply to elements in the document tree.
2882 <p>The following selector (CSS level 2) will <b>match</b> all anchors <code>a</code>
2883 with attribute <code>name</code> set inside a section 1 header <code>h1</code>:
2884 <pre>h1 a[name]</pre>
2886 <p>All CSS declarations attached to such a selector are applied to elements
2887 matching it. </div>
2891 <tbody>
2892 <tr>
2894 <tr>
2895 <th>Specification</th>
2896 <td>STTS 3</td>
2897 </tr>
2898 <tr>
2899 <th>Accepts</th>
2900 <td>
2902 <p>type selectors<br>universal selectors<br>attribute selectors<br>class
2903 selectors<br>ID selectors<br>all structural pseudo-classes<br>
2904 all combinators
2906 <p>namespaces</td></tr>
2907 <tr>
2908 <th>Excludes</th>
2909 <td>non-accepted pseudo-classes<br>pseudo-elements<br></td></tr>
2910 <tr>
2911 <th>Extra constraints</th>
2912 <td>some selectors and combinators are not allowed in fragment
2913 descriptions on the right side of STTS declarations.</td></tr></tbody></table>
2914 <form>
2940 </form>
2942 <p>Selectors can be used in STTS 3 in two different
2943 manners:
2944 <ol>
2945 <li>a selection mechanism equivalent to CSS selection mechanism: declarations
2946 attached to a given selector are applied to elements matching that selector,
2947 <li>fragment descriptions that appear on the right side of declarations.
2948 </li></ol></div>
2950 <h2><a name=Conformance></a>13. Conformance and requirements</h2>
2952 <p>This section defines conformance with the present specification only.
2954 <p>The inability of a user agent to implement part of this specification due to
2955 the limitations of a particular device (e.g., non interactive user agents will
2956 probably not implement dynamic pseudo-classes because they make no sense without
2957 interactivity) does not imply non-conformance.
2959 <p>All specifications reusing Selectors must contain a <a
2961 subset of Selectors it accepts or excludes, and describing the constraints
2962 it adds to the current specification.
2964 <p>Invalidity is caused by a parsing error, e.g. an unrecognized token or a token
2965 which is not allowed at the current parsing point.
2967 <p>User agents must observe the rules for handling parsing errors:
2968 <ul>
2969 <li>a simple selector containing an undeclared namespace prefix is invalid</li>
2970 <li>a selector containing an invalid simple selector, an invalid combinator
2971 or an invalid token is invalid. </li>
2972 <li>a group of selectors containing an invalid selector is invalid.</li>
2973 </ul>
2976 errors. (In the case of CSS, the entire rule in which the selector is
2977 used is dropped.)</p>
2979 <!-- Apparently all these references are out of date:
2980 <p>Implementations of this specification must behave as
2982 when parsing selectors and attempting matches. (In particular,
2983 implementations must assume the data is normalized and must not
2984 normalize it.) Normative rules for matching strings are defined in
2987 specification.</p>-->
2989 <h2><a name=Tests></a>14. Tests</h2>
2991 <p>This specification has <a
2993 suite</a> allowing user agents to verify their basic conformance to
2994 the specification. This test suite does not pretend to be exhaustive
2995 and does not cover all possible combined cases of Selectors.</p>
2997 <h2><a name=ACKS></a>15. Acknowledgements</h2>
2999 <p>The CSS working group would like to thank everyone who has sent
3000 comments on this specification over the years.</p>
3002 <p>The working group would like to extend special thanks to Donna
3003 McManus, Justin Baker, Joel Sklar, and Molly Ives Brower who perfermed
3004 the final editorial review.</p>
3006 <h2><a name=references>16. References</a></h2>
3010 <dt>[CSS1]
3011 <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
3014 <dt>[CSS21]
3015 <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
3018 <dt>[CWWW]
3019 <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
3022 <dt>[FLEX]
3023 <dd><a name="refsFLEX"></a> "<cite>Flex: The Lexical Scanner Generator</cite>", Version 2.3.7, ISBN 1882114213
3025 <dt>[HTML4]
3026 <dd><a name="refsHTML4"></a> Dave Ragget, Arnaud Le Hors, Ian Jacobs, editors; "<cite>HTML 4.01 Specification</cite>", W3C Recommendation, 24 December 1999
3029 <dt>[MATH]
3030 <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
3031 <dd>(<code><a href="http://www.w3.org/TR/REC-MathML/">http://www.w3.org/TR/REC-MathML/</a></code>)
3033 <dt>[RFC3066]
3034 <dd><a name="refsRFC3066"></a> H. Alvestrand; "<cite>Tags for the Identification of Languages</cite>", Request for Comments 3066, January 2001
3035 <dd>(<a href="http://www.ietf.org/rfc/rfc3066.txt"><code>http://www.ietf.org/rfc/rfc3066.txt</code></a>)
3037 <dt>[STTS]
3038 <dd><a name=refsSTTS></a> Daniel Glazman; "<cite>Simple Tree Transformation Sheets 3</cite>", Electricité de France, submission to the W3C, 11 November 1998
3039 <dd>(<code><a href="http://www.w3.org/TR/NOTE-STTS3">http://www.w3.org/TR/NOTE-STTS3</a></code>)
3041 <dt>[SVG]
3042 <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
3045 <dt>[UNICODE]</dt>
3047 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>.
3048 <dd>(<code><a href="http://www.unicode.org/versions/">http://www.unicode.org/versions/</a></code>)</dd>
3050 <dt>[XML10]
3051 <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
3054 <dt>[XMLNAMES]
3055 <dd><a name="refsXMLNAMES"></a> Tim Bray, Dave Hollander, Andrew Layman, editors; "<cite>Namespaces in XML</cite>", W3C Recommendation, 14 January 1999
3056 <dd>(<a href="http://www.w3.org/TR/REC-xml-names/"><code>http://www.w3.org/TR/REC-xml-names/</code></a>)
3058 <dt>[YACC]
3059 <dd><a name="refsYACC"></a> S. C. Johnson; "<cite>YACC — Yet another compiler compiler</cite>", Technical Report, Murray Hill, 1975
3061 </dl>
3062 </body>
3063 </html>