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LC 1307 NOT SATISFIED Re: Your comments on WCAG 2.0 Last Call Draft of April 2006

From: Charles McCathieNevile <chaals@opera.com>
Date: Mon, 11 Jun 2007 13:06:22 +0200
To: "Loretta Guarino Reid" <lorettaguarino@google.com>
Cc: public-comments-WCAG20@w3.org
Message-ID: <op.ttq7swz3wxe0ny@widsith.local>

On Fri, 18 May 2007 01:28:47 +0200, Loretta Guarino Reid  
<lorettaguarino@google.com> wrote:

> ----------------------------------------------------------
> Comment 3:
>
> Source:  
> http://www.w3.org/mid/op.tbjxedeqwxe0ny@researchsft.myhome.westell.com
> (Issue ID: LC-1307)
>
> Structural/substantive issue
>
> The specification seems to take no account of situations where in fact  
> all user agents relevant to a given baseline offer functionality that
> the guidelines are requiring of authors.
>
> Where this is the case (for example, SVG user agents generally provide a
> mechanism to pause any animation independently of the content, and in SVG
> tiny it is not possible to provide the functionality in content anyway)
> the guidelines should take it into account.
>
> I propose that the baseline section be reworked, to incorporate this type
> of situation. Perhaps the most robust way of specifying this would be to
> explicitly relate UAAG requirements to WCAG requirements, and note that
> where there are (some expression for most or all) user agents for the
> baseline which meet a given UAAG requirement the corresponding WCAG
> requirement need not be met. Note that the proportion of user agents for
> which this needs to be true should be at least as high, and probably
> higher than that which is reasonable to justify the use of a particular
> baseline in the first place.
>
> ----------------------------
> Response from Working Group:
> ----------------------------
>
> WCAG success criteria have been written to describe the functionality
> that must be available, but have avoided specifying that the
> functionality must be provided by the user agent or by the content
> directly. For example, SC 2.4.1 (A mechanism is available to bypass
> blocks of content that are repeated on multiple Web pages) can be
> satisfied by providing links in the content to bypass the blocks, or
> by providing headings at the beginning of each section and relying on
> the user agent to skip the repeated content by skipping to headings.
>
> ----------------------------------------------------------

Unfortunately, there is no clarity in what user agents are to be counted  
in the notion of "accessibility-supported", so it is not possible to make  
a rational (as opposed to arbitrary or wishful) determination of whether  
this is the case. As a single example, the Working Group has not resolved  
the question of whether Zoom support in HTML (even in the limited terms  
that the working group understands that) is sufficient in current user  
agents to determine whether it can be relied on.

This suggests that the practical problem of determining whether support is  
available still exists. This issue could well be resolved by an  
appropriate resolution to LC-1302 but I currently consider that it is not  
satisfactorily resolved in the current draft.

Cheers

Chaals

-- 
   Charles McCathieNevile, Opera Software: Standards Group
   hablo español  -  je parle français  -  jeg lærer norsk
chaals@opera.com  Catch up: Speed Dial  http://opera.com
Received on Monday, 11 June 2007 11:06:43 UTC

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