- From: Ian Jacobs <ij@w3.org>
- Date: Tue, 16 Jan 2001 23:42:58 -0500
- To: w3c-wai-ua@w3.org
Hello, Surprise! I've published the 16 January 2001 version of the Guidelines [1] (the techniques [2] are unchanged). I published this version because I was unhappy with the conformance model of the 13 January 2001 draft. There are a few editorial changes in the document based on some comments from Eric Hansen, but the primary change is that the conformance model has been revised. While it resembles the previous versions, I think it gets rid of some bugs. I encourage review of section 3 (Conformance [3]) because I want to be sure that the Working Group agrees with this approach. Here is the problem: WCAG 1.0 (by comparison) has only three ways to conform: A, Double-A, or Triple-A. We have a lot more permutations because we allow variable support for content types and input modalities, in addition to the A/Double-A/Triple-A conformance levels. You count the permutations: 3 Conformance levels times 7 Content type labels times 2 Input modality labels I believe that's 42 permutations, and you can add "applicability" to that... We don't have 42+ different labels to indicate conformance, so this version of the document introduces only two: unconditional conformance (the user agent satisfies all the requirements) and conditional conformance (the user agent satisfies fewer than all requirements, in a well-defined manner). However, with that means that two user agents that conform conditionally may differ greatly in the requirements they satisfy. The only reason I'm willing to live with that situation is that any valid conformance claim MUST indicate which requirements the user agent does not meet. It does this through conformance levels, content type labels, input modality labels, and assertions about applicability. Thus, two user agents may conform conditionally and satisfy very different requirements. But two claims of conformance must state these differences in detail. Last big change: the definition of a "valid claim" now includes three conditions: 1.The claim is well-formed. 2.The claim indicates which requirements the user agent does not satisfy through one conformance level and any relevant content type labels, input modality labels, and applicability information. 3.It is verified that the user agent satisfies all other requirements not exempted by the claim through these mechanisms. The third condition introduces the word "verified" for the first time. The document doesn't explain HOW one verifies that a requirement has been satisfied, but that's always been a limitation of the document. (Recall that WAI doesn't certify claims today either.) Comments welcome, - Ian P.S. I don't intend to publish a new draft every three days. If the conformance model is still broken, I will not republish immediately to correct it. [1] http://www.w3.org/WAI/UA/WD-UAAG10-20010116/ [2] http://www.w3.org/WAI/UA/WD-UAAG10-TECHS-20010116/ [3] http://www.w3.org/WAI/UA/WD-UAAG10-20010116/#Conformance -- Ian Jacobs (jacobs@w3.org) http://www.w3.org/People/Jacobs Tel: +1 831 457-2842 Cell: +1 917 450-8783
Received on Tuesday, 16 January 2001 23:43:06 UTC