- From: Jukka K. Korpela <jkorpela@cs.tut.fi>
- Date: Mon, 28 Mar 2005 20:57:12 +0300 (EEST)
- To: Bill Milbratz <bmilbratz@outstart.com>
- Cc: www-validator@w3.org
On Mon, 28 Mar 2005, Bill Milbratz wrote: > I haven't seen a '508' or 'html accessibility' dtd. And you won't, since accessibility (and even the simplistic technical rules that 508 is about) goes far beyond what can be expressed in a DTD. For example, you _can_ say in a DTD that every <img> element must have an alt attribute - but that's what current HTML DTDs say anyway. You _could_ similarly say that every <table> must have a summary attribute, but that would be questionable. You cannot say that a <table> inside a <table> must have a summary attribute, for example. Still less can you refer to "tables with two or more logical levels of depth", which is a logical, not syntactic concept. And you cannot say that <th> must be used for headers, since there's no way to express such a requirement in a DTD. (Besides, the requirement itself contradicts HTML specifications, which say that if a cell acts both as a header and as data - whatever that means! - then <td> should be used.) There's not much you can do to improve current HTML DTDs to detect accessibility problems. Requiring a lang attribute in <html> comes into my mind. -- Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/
Received on Monday, 28 March 2005 17:57:45 UTC