Re: Should validity be P1 or P2? (was RE: summary of resolutions from last 2 days)

Jason notes that for my DHTML roadmap example:
<blockquote>
In your definition of validity you didn't specify which DTD or schema 
the document instance had to conform to, or that it must be a DTD/schema 
published by the W3C or comparable body.

Thus I assume you could live with:

Level 1: content written in an XML-based markup languages must validate 
to a DTD or schema.

Level 2: Same as level 1, but the DTD/schema must be that of a standard 
published by the W3C or a comparable body.
</blockquote>

Right, I was not specific.  I have DHTML roadmap examples that are 
implemented in XHTML 1.0 that work, are accessible but do not validate. In 
order to validate in XHTML I would have to create a new DTD and make it 
publically available if I want others to be able to use the technology. I 
can live with your proposals in an XHTML world but HTML offers no 
mechanism for extension. So, I may be able to do some creative things to 
improve accessibility in HTML but I would not be able to use them because 
I am making use of user agent extensions which are not in any DTD or 
schema.  So, I would not be able to claim WCAG conformance because I can't 
validate. 

There are similar issues for XHTML 1.1 although the DTD can be more easily 
extended through modules.   The problem with using XHTML 1.1, however, is 
that the content-type should be application/xhtml+xml which IE, with 
approximately 90% market share, does not support.  So, I can create a DTD 
for XHTML 1.1 and pass validation but I have to serve up that XHTML 1.1 
page to IE with a content-type of text/html which the W3C explicitly does 
not recommend [1]. 

I certainly agree that developers should produce valid code and use the 
mechanisms of the W3C to improve and update specifications to support new 
technologies. I am just against requiring it at level 1 in the Web Content 
Accessibility Guidelines since validation against a specification does not 
always improve accessibility and may inhibit innovation in the short term. 
 


[1] http://www.w3.org/TR/xhtml-media-types/#summary


Becky Gibson
Web Accessibility Architect
                                                       
IBM Emerging Internet Technologies
5 Technology Park Drive
Westford, MA 01886
Voice: 978 399-6101; t/l 333-6101
Email: gibsonb@us.ibm.com