forked from w3c/csswg-drafts
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathOverview.html
More file actions
4847 lines (3676 loc) · 185 KB
/
Overview.html
File metadata and controls
4847 lines (3676 loc) · 185 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html lang=en>
<head profile="http://dublincore.org/documents/2008/08/04/dc-html/ ">
<meta charset=utf8>
<title>Selectors Level 4</title>
<link href="http://purl.org/dc/terms/" rel=schema.dcterms>
<link href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel=dcterms.rights>
<meta content="Selectors Level 4" name=dcterms.title>
<meta content=text name=dcterms.type>
<meta content=2013-10-18 name=dcterms.date>
<meta content="Elika J. Etemad" name=dcterms.creator>
<meta content="Tab Atkins Jr." name=dcterms.creator>
<meta content=W3C name=dcterms.publisher>
<meta content="http://dev.w3.org/csswg/selectors4/"
name=dcterms.identifier>
<link href="../default.css" rel=stylesheet type="text/css">
<style type="text/css">
.tprofile td, th { vertical-align: baseline; padding: 0 0.5em; }
.tprofile th { text-align: right; }
</style>
<link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
type="text/css">
<body>
<div class=head> <!--begin-logo-->
<p><a href="http://www.w3.org/"><img alt=W3C height=48
src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
<h1 id=title>Selectors Level 4</h1>
<h2 class="no-num no-toc">Editor's Draft 18 October 2013</h2>
<dl>
<dt>This version:
<dd><a href="http://dev.w3.org/csswg/selectors4/">
http://www.w3.org/TR/2013/ED-selectors4-20131018/</a>
<dt>Editor's draft:
<dd><a href="http://dev.w3.org/csswg/selectors4/">
http://dev.w3.org/csswg/selectors4/</a>
<dt>Latest version of Selectors Level 4:
<dd><a href="http://www.w3.org/TR/selectors4/">
http://www.w3.org/TR/selectors4/</a>
<dt>Latest Selectors specification:
<dd><a href="http://www.w3.org/TR/selectors/">
http://www.w3.org/TR/selectors/</a>
<dt>Previous version:
<dd><a href="http://www.w3.org/TR/2011/WD-selectors4-20110929/">
http://www.w3.org/TR/2011/WD-selectors4-20110929/</a>
<dt>Feedback:
<dd><a
href="mailto:www-style@w3.org?subject=%5Bselectors4%5D%20feedback">www-style@w3.org</a>
with subject line “<kbd>[selectors4] <var>… message topic
…</var></kbd>” (<a
href="http://lists.w3.org/Archives/Public/www-style/"
rel=discussion>archives</a>)
<dt>Editors:
<dd class=vcard><a class="url fn"
href="http://fantasai.inkedblade.net/contact">Elika J. Etemad</a>
(Mozilla)
<dd class=vcard> <a class="url fn"
href="http://www.xanthir.com/contact/">Tab Atkins Jr.</a> (<span
class=org>Google</span>)
<dt>Previous Editors:
<dd class=vcard><a class="url fn" href="http://www.tantek.com/"
lang=tr>Tantek Çelik</a> (Microsoft)
<dd class=vcard><span class=fn>Daniel Glazman</span> (Disruptive
Innovations SARL)
<dd class=vcard><span class=fn>Ian Hickson</span> (Opera Softare ASA)
<dd class=vcard><span class=fn>Peter Linss</span> (Netscape/AOL)
<dd class=vcard><span class=fn>John Williams</span> (Quark, Inc.)
</dl>
<!--begin-copyright-->
<p class=copyright><a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel=license>Copyright</a> © 2013 <a href="http://www.w3.org/"><abbr
title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a
href="http://www.csail.mit.edu/"><abbr
title="Massachusetts Institute of Technology">MIT</abbr></a>, <a
href="http://www.ercim.eu/"><abbr
title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>,
<a href="http://www.keio.ac.jp/">Keio</a>, <a
href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved. W3C <a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
<a
href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
and <a
href="http://www.w3.org/Consortium/Legal/copyright-documents">document
use</a> rules apply.</p>
<!--end-copyright-->
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc" id=abstract> Abstract</h2>
<p><a href="#selector"><em>Selectors</em></a> are patterns that match
against elements in a tree, and as such form one of several technologies
that can be used to select nodes in an XML document. Selectors have been
optimized for use with HTML and XML, and are designed to be usable in
performance-critical code. They are a core component of <abbr
title="Cascading Style Sheets">CSS</abbr> (Cascading Style Sheets), which
uses Selectors to bind style properties to elements in the document.
<p>Selectors Level 4 describes the selectors that already exist in <a
href="#ref-SELECT" rel=biblioentry>[SELECT]<!--{{!SELECT}}--></a>, and
further introduces new selectors for CSS and other languages that may need
them.
<h2 class="no-num no-toc" id=status>Status of this Document</h2>
<!--begin-status-->
<p>This is a public copy of the editors' draft. It is provided for
discussion only and may change at any moment. Its publication here does
not imply endorsement of its contents by W3C. Don't cite this document
other than as work in progress.
<p>The (<a
href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
mailing list <a
href="mailto:www-style@w3.org?Subject=%5Bselectors4%5D%20PUT%20SUBJECT%20HERE">
www-style@w3.org</a> (see <a
href="http://www.w3.org/Mail/Request">instructions</a>) is preferred for
discussion of this specification. When sending e-mail, please put the text
“selectors4” in the subject, preferably like this:
“[<!---->selectors4<!---->] <em>…summary of comment…</em>”
<p>This document was produced by the <a
href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
the <a href="http://www.w3.org/Style/">Style Activity</a>).
<p>This document was produced by a group operating under the <a
href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
2004 W3C Patent Policy</a>. W3C maintains a <a
href="http://www.w3.org/2004/01/pp-impl/32061/status"
rel=disclosure>public list of any patent disclosures</a> made in
connection with the deliverables of the group; that page also includes
instructions for disclosing a patent. An individual who has actual
knowledge of a patent which the individual believes contains <a
href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a
href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
6 of the W3C Patent Policy</a>.</p>
<!--end-status-->
<p>This module is a somewhat-unstable Working Draft. <strong>If you are
looking for a stable Selectors specification, use <a
href="http://www.w3.org/TR/css3-selectors/">Selectors 3</a>.</strong> Read
the <a href="http://www.w3.org/TR/CSS/">CSS Snapshot</a> for an overview
of the CSS development process. See the <a href="#overview">Selectors
Overview</a> for a summary of additions to level 3.
<p>The following features are at-risk and may be dropped during the CR
period if there is not sufficient implementer interest: the reference
combinator, the column combinator, the ‘<code
class=css>:invalid-drop</code>’ and ‘<code
class=css>:valid-drop</code>’ pseudo-classes.
<h2 class="no-num no-toc" id=contents>Table of Contents</h2>
<!--begin-toc-->
<ul class=toc>
<li><a href="#context"><span class=secno>1. </span> Introduction</a>
<ul class=toc>
<li><a href="#placement"><span class=secno>1.1. </span>Module
Interactions</a>
</ul>
<li><a href="#overview"><span class=secno>2. </span> Selectors
Overview</a>
<ul class=toc>
<li><a href="#profiles"><span class=secno>2.1. </span> <i>Fast</i> vs
<i>Complete</i> Selector Profiles</a>
</ul>
<li><a href="#syntax"><span class=secno>3. </span> Selector Syntax and
Structure</a>
<ul class=toc>
<li><a href="#structure"><span class=secno>3.1. </span> Structure and
Terminology</a>
<li><a href="#subject"><span class=secno>3.2. </span> Determining the
Subject of a Selector</a>
<li><a href="#scoping"><span class=secno>3.3. </span> Scoped
Selectors</a>
<li><a href="#relative"><span class=secno>3.4. </span> Relative
Selectors</a>
<ul class=toc>
<li><a href="#absolutizing"><span class=secno>3.4.1. </span>
Absolutizing a Relative Selector</a>
</ul>
<li><a href="#pseudo-classes"><span class=secno>3.5. </span>
Pseudo-classes</a>
<li><a href="#pseudo-elements"><span class=secno>3.6.
</span>Pseudo-elements</a>
<li><a href="#case-sensitive"><span class=secno>3.7. </span> Characters
and case sensitivity</a>
<li><a href="#namespaces"><span class=secno>3.8. </span> Namespaces</a>
<li><a href="#invalid"><span class=secno>3.9. </span> Invalid Selectors
and Error Handling</a>
</ul>
<li><a href="#logical-combination"><span class=secno>4. </span> Logical
Combinations</a>
<ul class=toc>
<li><a href="#grouping"><span class=secno>4.1. </span> Selector
Lists</a>
<li><a href="#matches"><span class=secno>4.2. </span> The Matches-Any
Pseudo-class: <code>:matches()</code></a>
<li><a href="#negation"><span class=secno>4.3. </span> The Negation
Pseudo-class: <code>:not()</code></a>
</ul>
<li><a href="#elemental-selectors"><span class=secno>5. </span> Elemental
selectors</a>
<ul class=toc>
<li><a href="#type-selectors"><span class=secno>5.1. </span> Type (tag
name) selector</a>
<ul class=toc>
<li><a href="#typenmsp"><span class=secno>5.1.1. </span> Type
selectors and namespaces</a>
</ul>
<li><a href="#universal-selector"><span class=secno>5.2. </span>
Universal selector </a>
<ul class=toc>
<li><a href="#univnmsp"><span class=secno>5.2.1. </span> Universal
selector and namespaces</a>
</ul>
</ul>
<li><a href="#attribute-selectors"><span class=secno>6. </span> Attribute
selectors</a>
<ul class=toc>
<li><a href="#attribute-representation"><span class=secno>6.1. </span>
Attribute presence and value selectors</a>
<li><a href="#attribute-substrings"><span class=secno>6.2. </span>
Substring matching attribute selectors</a>
<li><a href="#attribute-case"><span class=secno>6.3. </span>
Case-sensitivity</a>
<li><a href="#attrnmsp"><span class=secno>6.4. </span> Attribute
selectors and namespaces</a>
<li><a href="#def-values"><span class=secno>6.5. </span> Default
attribute values in DTDs</a>
<li><a href="#class-html"><span class=secno>6.6. </span> Class
selectors</a>
<li><a href="#id-selectors"><span class=secno>6.7. </span> ID
selectors</a>
</ul>
<li><a href="#linguistic-pseudos"><span class=secno>7. </span> Linguistic
Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-dir-pseudo"><span class=secno>7.1. </span> The
directionality pseudo-class <code>:dir()</code></a>
<li><a href="#the-lang-pseudo"><span class=secno>7.2. </span> The
language pseudo-class <code>:lang()</code></a>
</ul>
<li><a href="#location"><span class=secno>8. </span> Location
Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-any-link-pseudo"><span class=secno>8.1. </span> The
hyperlink pseudo-class: <code>:any-link</code></a>
<li><a href="#link"><span class=secno>8.2. </span> The link history
pseudo-classes: <code>:link</code> and <code>:visited</code></a>
<li><a href="#local-pseudo"><span class=secno>8.3. </span> The local
link pseudo-class <code>:local-link</code></a>
<li><a href="#the-target-pseudo"><span class=secno>8.4. </span> The
target pseudo-class <code>:target</code></a>
<li><a href="#the-scope-pseudo"><span class=secno>8.5. </span> The
reference element pseudo-class <code>:scope</code></a>
</ul>
<li><a href="#useraction-pseudos"><span class=secno>9. </span> User Action
Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-hover-pseudo"><span class=secno>9.1. </span> The
pointer hover pseudo-class <code>:hover</code></a>
<li><a href="#the-active-pseudo"><span class=secno>9.2. </span> The
activation pseudo-class <code>:active</code></a>
<li><a href="#the-focus-pseudo"><span class=secno>9.3. </span> The input
focus pseudo-class <code>:focus</code></a>
<li><a href="#drag-pseudos"><span class=secno>9.4. </span> The
drag-and-drop pseudo-class <code>:drop</code> and
<code>:drop()</code></a>
</ul>
<li><a href="#time-pseudos"><span class=secno>10. </span> Time-dimensional
Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-current-pseudo"><span class=secno>10.1. </span> The
current-element pseudo-class <code>:current</code></a>
<li><a href="#the-past-pseudo"><span class=secno>10.2. </span> The
past-element pseudo-class <code>:past</code></a>
<li><a href="#the-future-pseudo"><span class=secno>10.3. </span> The
future-element pseudo-class <code>:future</code></a>
</ul>
<li><a href="#input-pseudos"><span class=secno>11. </span> The Input
Pseudo-classes</a>
<ul class=toc>
<li><a href="#input-states"><span class=secno>11.1. </span> Input
Control States</a>
<ul class=toc>
<li><a href="#enableddisabled"><span class=secno>11.1.1. </span> The
<code>:enabled</code> and <code>:disabled</code> pseudo-classes</a>
<li><a href="#rw-pseudos"><span class=secno>11.1.2. </span> The
mutability pseudo-classes <code>:read-only</code> and
<code>:read-write</code></a>
<li><a href="#placeholder"><span class=secno>11.1.3. </span> The
placeholder-shown pseudo-class <code>:placeholder-shown</code></a>
<li><a href="#the-default-pseudo"><span class=secno>11.1.4. </span>
The default-option pseudo-class <code>:default</code></a>
</ul>
<li><a href="#input-value-states"><span class=secno>11.2. </span> Input
Value States</a>
<ul class=toc>
<li><a href="#checked"><span class=secno>11.2.1. </span> The
selected-option pseudo-class <code>:checked</code></a>
<li><a href="#indeterminate"><span class=secno>11.2.2. </span> The
indeterminate-value pseudo-class <code>:indeterminate</code></a>
</ul>
<li><a href="#ui-validity"><span class=secno>11.3. </span> Input
Value-checking</a>
<ul class=toc>
<li><a href="#validity-pseudos"><span class=secno>11.3.1. </span> The
validity pseudo-classes: <code>:valid</code> and
<code>:invalid</code></a>
<li><a href="#range-pseudos"><span class=secno>11.3.2. </span> The
range pseudo-classes <code>:in-range</code> and
<code>:out-of-range</code></a>
<li><a href="#opt-pseudos"><span class=secno>11.3.3. </span> The
optionality pseudo-classes <code>:required</code> and
<code>:optional</code></a>
<li><a href="#user-pseudos"><span class=secno>11.3.4. </span> The
user-interaction pseudo-class <code>:user-error</code></a>
</ul>
</ul>
<li><a href="#structural-pseudos"><span class=secno>12. </span>
Tree-Structural pseudo-classes</a>
<ul class=toc>
<li><a href="#the-root-pseudo"><span class=secno>12.1. </span>
<code>:root</code> pseudo-class</a>
<li><a href="#the-empty-pseudo"><span class=secno>12.2. </span>
<code>:empty</code> pseudo-class</a>
<li><a href="#the-blank-pseudo"><span class=secno>12.3. </span>
<code>:blank</code> pseudo-class</a>
<li><a href="#anb"><span class=secno>12.4. </span> Indexed
Pseudo-classes: the <var>An+B</var> micro-syntax</a>
<ul class=toc>
<li><a href="#anb-syntax"><span class=secno>12.4.1. </span> Syntax</a>
<li><a href="#anb-grammar"><span class=secno>12.4.2. </span>
Grammar</a>
</ul>
<li><a href="#child-index"><span class=secno>12.5. </span> Child-indexed
Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-nth-child-pseudo"><span class=secno>12.5.1. </span>
<code>:nth-child()</code> pseudo-class</a>
<li><a href="#the-nth-last-child-pseudo"><span class=secno>12.5.2.
</span> <code>:nth-last-child()</code> pseudo-class</a>
<li><a href="#the-first-child-pseudo"><span class=secno>12.5.3.
</span> <code>:first-child</code> pseudo-class</a>
<li><a href="#the-last-child-pseudo"><span class=secno>12.5.4. </span>
<code>:last-child</code> pseudo-class</a>
<li><a href="#the-only-child-pseudo"><span class=secno>12.5.5. </span>
<code>:only-child</code> pseudo-class</a>
</ul>
<li><a href="#typed-child-index"><span class=secno>12.6. </span> Typed
Child-indexed Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-nth-of-type-pseudo"><span class=secno>12.6.1.
</span> <code>:nth-of-type()</code> pseudo-class</a>
<li><a href="#the-nth-last-of-type-pseudo"><span class=secno>12.6.2.
</span> <code>:nth-last-of-type()</code> pseudo-class</a>
<li><a href="#the-first-of-type-pseudo"><span class=secno>12.6.3.
</span> <code>:first-of-type</code> pseudo-class</a>
<li><a href="#the-last-of-type-pseudo"><span class=secno>12.6.4.
</span> <code>:last-of-type</code> pseudo-class</a>
<li><a href="#the-only-of-type-pseudo"><span class=secno>12.6.5.
</span> <code>:only-of-type</code> pseudo-class</a>
</ul>
<li><a href="#selected-child-index"><span class=secno>12.7. </span>
Selected Child-indexed Pseudo-classes</a>
<ul class=toc>
<li><a href="#the-nth-match-pseudo"><span class=secno>12.7.1. </span>
<code>:nth-match()</code> pseudo-class</a>
<li><a href="#the-nth-last-match-pseudo"><span class=secno>12.7.2.
</span> <code>:nth-last-match()</code> pseudo-class</a>
</ul>
</ul>
<li><a href="#combinators"><span class=secno>13. </span> Combinators</a>
<ul class=toc>
<li><a href="#descendant-combinators"><span class=secno>13.1. </span>
Descendant combinator (<code> </code>)</a>
<li><a href="#child-combinators"><span class=secno>13.2. </span> Child
combinator (<code>></code>)</a>
<li><a href="#adjacent-sibling-combinators"><span class=secno>13.3.
</span> Next-sibling combinator (<code>+</code>)</a>
<li><a href="#general-sibling-combinators"><span class=secno>13.4.
</span> Following-sibling combinator (<code>~</code>)</a>
<li><a href="#idref-combinators"><span class=secno>13.5. </span>
Reference combinators <code>/ref/</code></a>
</ul>
<li><a href="#table-pseudos"><span class=secno>14. </span> Grid-Structural
Selectors</a>
<ul class=toc>
<li><a href="#column-combinator"><span class=secno>14.1. </span> Column
combinator</a>
<li><a href="#the-nth-column-pseudo"><span class=secno>14.2. </span>
<code>:nth-column()</code> pseudo-class</a>
<li><a href="#the-nth-last-column-pseudo"><span class=secno>14.3.
</span> <code>:nth-last-column()</code> pseudo-class</a>
</ul>
<li><a href="#specificity"><span class=secno>15. </span> Calculating a
selector's specificity</a>
<li><a href="#grammar"><span class=secno>16. </span> Grammar</a>
<li><a href="#api-hooks"><span class=secno>17. </span> API Hooks</a>
<ul class=toc>
<li><a href="#parse-a-selector"><span class=secno>17.1. </span> Parse A
Selector</a>
<li><a href="#parse-a-relative-selector"><span class=secno>17.2. </span>
Parse A Relative Selector</a>
<li><a href="#match-a-selector"><span class=secno>17.3. </span> Match A
Selector</a>
</ul>
<li><a href="#changes"><span class=secno>18. </span> Changes</a>
<li><a href="#conformance"><span class=secno>19. </span> Conformance</a>
<ul class=toc>
<li><a href="#conventions"><span class=secno>19.1. </span>Document
Conventions</a>
<li><a href="#conformance-classes"><span class=secno>19.2. </span>
Conformance Classes</a>
<li><a href="#partial"><span class=secno>19.3. </span> Partial
Implementations</a>
<li><a href="#experimental"><span class=secno>19.4. </span> Experimental
Implementations</a>
</ul>
<li><a href="#acknowledgements"><span class=secno>20. </span>
Acknowledgements</a>
<li><a href="#references"><span class=secno>21. </span> References</a>
<ul class=toc>
<li><a href="#normative-references"><span class=secno>21.1. </span>
Normative References</a>
<li><a href="#informative-references"><span class=secno>21.2. </span>
Informative References</a>
</ul>
</ul>
<!--end-toc-->
<h2 id=context><span class=secno>1. </span> Introduction</h2>
<p><em>This section is not normative.</em>
<p> A selector is a boolean predicate that takes an element in a tree
structure and tests whether the element matches the selector or not.
<p> These expressions may be used for many things:
<ul>
<li> directly on an element to test whether it matches some criteria, such
as in the <code>Element.matches()</code> function defined in <a
href="#ref-SELECTORS-API2"
rel=biblioentry>[SELECTORS-API2]<!--{{SELECTORS-API2}}--></a>
<li> applied to an entire tree of elements to filter it into a set of
elements that match the criteria, such as in the
<code>document.findAll()</code> function defined in <a
href="#ref-SELECTORS-API2"
rel=biblioentry>[SELECTORS-API2]<!--{{SELECTORS-API2}}--></a> or the
selector of a CSS style rule.
<li> used "in reverse" to generate markup that would match a given
selector, such as in <a href="http://haml.info/">HAML</a> or <a
href="http://en.wikipedia.org/wiki/Zen_Coding">Zen Coding</a>
</ul>
<p> Selectors Levels 1, 2, and 3 are defined as the subsets of selector
functionality defined in the <a
href="http://www.w3.org/TR/REC-CSS1">CSS1</a>, <a
href="http://www.w3.org/TR/CSS21/">CSS2.1</a>, and <a
href="http://www.w3.org/TR/css3-selectors/">Selectors Level 3</a>
specifications, respectively. This module defines Selectors Level 4.
<h3 id=placement><span class=secno>1.1. </span>Module Interactions</h3>
<p>This module replaces the definitions of and extends the set of selectors
defined for CSS in <a href="#ref-SELECT"
rel=biblioentry>[SELECT]<!--{{SELECT}}--></a> and <a href="#ref-CSS21"
rel=biblioentry>[CSS21]<!--{{CSS21}}--></a>.
<p> Pseudo-element selectors, which define abstract elements in a rendering
tree, are not part of this specification: their generic syntax is
described here, but, due to their close integration with the rendering
model and irrelevance to other uses such as DOM queries, they will be
defined in other modules.
<h2 id=overview><span class=secno>2. </span> Selectors Overview</h2>
<p><em>This section is non-normative, as it merely summarizes the following
sections.</em>
<p>A Selector represents a structure. This structure can be used as a
condition (e.g. in a CSS rule) that determines which elements a selector
matches in the document tree, or as a flat description of the HTML or XML
fragment corresponding to that structure.
<p>Selectors may range from simple element names to rich contextual
representations.
<p>The following table summarizes the Selector syntax:
<table class=data><col class=pattern><col class=meaning><col
class=section><col class=level>
<thead>
<tr>
<th>Pattern
<th>Represents
<th>Section
<th>Level
<tbody>
<tr>
<td><code>*</code>
<td>any element
<td><a href="#universal-selector">Universal selector</a>
<td>2
<tr>
<td><code>E</code>
<td>an element of type E
<td><a href="#type-selectors">Type (tag name) selector</a>
<td>1
<tbody>
<tr>
<td><code>E:not(<var>s1</var>, <var>s2</var>)</code>
<td>an E element that does not match either <a
href="#compound"><i>compound selector</i></a> <var>s1</var> or <a
href="#compound"><i>compound selector</i></a> <var>s2</var>
<td><a href="#negation">Negation pseudo-class</a>
<td>3/4
<tr>
<td><code>E:matches(<var>s1</var>, <var>s2</var>)</code>
<td>an E element that matches <a href="#compound"><i>compound
selector</i></a> <var>s1</var> and/or <a href="#compound"><i>compound
selector</i></a> <var>s2</var>
<td><a href="#matches">Matches-any pseudo-class</a>
<td>4
<tbody>
<tr>
<td><code>E.warning</code>
<td>an E element belonging to the class <code>warning</code> (the
document language specifies how class is determined).
<td><a href="#class-html">Class selectors</a>
<td>1
<tr>
<td><code>E#myid</code>
<td>an E element with ID equal to <code>myid</code>.
<td><a href="#id-selectors">ID selectors</a>
<td>1
<tr>
<td><code>E[foo]</code>
<td>an E element with a <code>foo</code> attribute
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>2
<tr>
<td><code>E[foo="bar"]</code>
<td>an E element whose <code>foo</code> attribute value is exactly equal
to <code>bar</code>
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>2
<tr>
<td><code>E[foo="bar" i]</code>
<td>an E element whose <code>foo</code> attribute value is exactly equal
to any (ASCII-range) case-permutation of <code>bar</code>
<td><a href="#attribute-case">Attribute selectors: Case-sensitivity</a>
<td>4
<tr>
<td><code>E[foo~="bar"]</code>
<td>an E element whose <code>foo</code> attribute value is a list of
whitespace-separated values, one of which is exactly equal to
<code>bar</code>
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>2
<tr>
<td><code>E[foo^="bar"]</code>
<td>an E element whose <code>foo</code> attribute value begins exactly
with the string "bar"
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>3
<tr>
<td><code>E[foo$="bar"]</code>
<td>an E element whose <code>foo</code> attribute value ends exactly
with the string <code>bar</code>
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>3
<tr>
<td><code>E[foo*="bar"]</code>
<td>an E element whose <code>foo</code> attribute value contains the
substring <code>bar</code>
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>3
<tr>
<td><code>E[foo|="en"]</code>
<td>an E element whose <code>foo</code> attribute value is a
hyphen-separated list of values beginning with <code>en</code>
<td><a href="#attribute-selectors">Attribute selectors</a>
<td>2
<tbody>
<tr>
<td><code>E:dir(ltr)</code>
<td>an element of type E in with left-to-right directionality (the
document language specifies how directionality is determined)
<td><a href="#dir-pseudo">The :dir() pseudo-class</a>
<td>4
<tr>
<td><code>E:lang(zh, *-hant)</code>
<td>an element of type E tagged as being either in Chinese (any dialect
or writing system) or othewise written with traditional Chinese
characters
<td><a href="#lang-pseudo">The :lang() pseudo-class</a>
<td>2/4
<tbody>
<tr>
<td><code>E:any-link</code>
<td>an E element being the source anchor of a hyperlink
<td><a href="#any-link-pseudo">The hyperlink pseudo-class</a>
<td>4
<tr>
<td><code>E:link</code>
<td>an E element being the source anchor of a hyperlink of which the
target is not yet visited
<td><a href="#link">The link history pseudo-classes</a>
<td>1
<tr>
<td><code>E:visited</code>
<td>an E element being the source anchor of a hyperlink of which the
target is already visited
<td><a href="#link">The link history pseudo-classes</a>
<td>1
<tr>
<td><code>E:local-link</code>
<td>an E element being the source anchor of a hyperlink of which the
target is the current document
<td><a href="#local-pseudo">The local link pseudo-class</a>
<td>4
<tr>
<td><code>E:local-link(0)</code>
<td>an E element being the source anchor of a hyperlink of which the
target is within the current domain
<td><a href="#local-pseudo">The local link pseudo-class</a>
<td>4
<tr>
<td><code>E:target</code>
<td>an E element being the target of the referring URL
<td><a href="#target-pseudo">The target pseudo-class</a>
<td>3
<tr>
<td><code>E:scope</code>
<td>an E element being a designated reference element
<td><a href="#scope-pseudo">The scope pseudo-class</a>
<td>4
<tbody>
<tr>
<td><code>E:current</code>
<td>an E element that is currently presented in a time-dimensional
canvas
<td><a href="#time-pseudos">Time-dimensional Pseudo-classes</a>
<td>4
<tr>
<td><code>E:current(<var>s</var>)</code>
<td>an E element that is the deepest <a
href="#current-pseudo"><code>:current</code></a> element that matches
selector <var>s</var>
<td><a href="#time-pseudos">Time-dimensional Pseudo-classes</a>
<td>4
<tr>
<td><code>E:past</code>
<td>an E element that is in the past in a time-dimensional canvas
<td><a href="#time-pseudos">Time-dimensional Pseudo-classes</a>
<td>4
<tr>
<td><code>E:future</code>
<td>an E element that is in the future in a time-dimensional canvas
<td><a href="#time-pseudos">Time-dimensional Pseudo-classes</a>
<td>4
<tbody>
<tr>
<td><code>E:active</code>
<td>an E element that is in an activated state
<td><a href="#useraction-pseudos">The user action pseudo-classes</a>
<td>1
<tr>
<td><code>E:hover</code>
<td>an E element that is under the cursor, or that has a descendant
under the cursor
<td><a href="#useraction-pseudos">The user action pseudo-classes</a>
<td>2
<tr>
<td><code>E:focus</code>
<td>an E element that has user input focus
<td><a href="#useraction-pseudos">The user action pseudo-classes</a>
<td>2
<tr>
<td><code>E:active-drop</code>
<td>an E element that will receive the item currently being dragged
<td><a href="#drag-pseudos">The drag-and-drop pseudo-classes</a>
<td>4
<tr>
<td><code>E:valid-drop</code>
<td>an E element that could receive the item currently being dragged
<td><a href="#drag-pseudos">The drag-and-drop pseudo-classes</a>
<td>4
<tr>
<td><code>E:invalid-drop</code>
<td>an E element that cannot receive the item currently being dragged,
but could receive some other item
<td><a href="#drag-pseudos">The drag-and-drop pseudo-classes</a>
<td>4
<tbody>
<tr>
<td><code>E:enabled<br>
E:disabled</code>
<td>a user interface element E that is enabled or disabled, respectively
<td><a href="#enableddisabled">The :enabled and :disabled
pseudo-classes</a>
<td>3
<tr>
<td><code>E:read-only</code><br>
<code>E:read-write</code>
<td>a user interface element E that
<td><a href="#rw-pseudos">The mutability pseudo-classes</a>
<td>3-UI/4
<tr>
<td><code>E:placeholder-shown</code>
<td>an input control currently showing placeholder text
<td><a href="#rw-pseudos">The placeholder-shown pseudo-class</a>
<td>3-UI/4
<tr>
<td><code>E:default</code>
<td>a user interface element E that
<td><a href="#default-pseudo">The default option pseudo-class
:default</a>
<td>3-UI/4
<tr>
<td><code>E:checked</code>
<td>a user interface element E that is checked/selected (for instance a
radio-button or checkbox)
<td><a href="#checked">The selected-option pseudo-class</a>
<td>3
<tr>