16351 2012-03-13 23:33:00 +0000 For ease of interoperability with CSS, suggest adding an authoring recommendation that id attribute values consist of the characters A-Z, a-z, 0-9, _, - and not begin with a dash. 2012-08-29 05:46:19 +0000 1 1 1 Unclassified WHATWG HTML unspecified Other other RESOLVED WONTFIX http://www.whatwg.org/specs/web-apps/current-work/#the-id-attribute P3 normal Unsorted 1 contributor ian ian mike contributor oldest_to_newest 65488 0 contributor 2012-03-13 23:33:00 +0000 Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html Multipage: http://www.whatwg.org/C#the-id-attribute Complete: http://www.whatwg.org/c#the-id-attribute Comment: For ease of interoperability with CSS, suggest adding an authoring recommendation that id attribute values consist of the characters A-Z, a-z, 0-9, _, - and not begin with a dash. Posted from: 99.113.33.155 User agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.2) Gecko/20100101 Firefox/10.0.2 Iceweasel/10.0.2 65506 1 zcorpan 2012-03-14 07:49:58 +0000 Same with classes, I presume? What about data-* attribute names? Note that the rule is: "In CSS, identifiers (including element names, classes, and IDs in selectors) can contain only the characters [a-zA-Z0-9] and ISO 10646 characters U+00A0 and higher, plus the hyphen (-) and the underscore (_); they cannot start with a digit, two hyphens, or a hyphen followed by a digit." 70649 2 contributor 2012-07-18 17:14:39 +0000 This bug was cloned to create bug 18090 as part of operation convergence. 72899 3 ian 2012-08-28 18:55:11 +0000 You can use whatever characters you want in CSS. e.g.: <style> \# { color: green } </style> <p id="#">aha!</p> 72962 4 zcorpan 2012-08-29 05:46:19 +0000 (The selector should be #\#.)