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Re: [html4all] Discussion Action 54: First draft of the rewrite of "The img element"

From: Jason White <jason@jasonjgw.net>
Date: Tue, 13 May 2008 11:13:27 +1000
To: list@html4all.org, "public-html@w3.org" <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>, wai-liaison@w3.org
Message-ID: <20080513011327.GA6100@jdc.jasonjgw.net>

On Fri, May 09, 2008 at 04:06:32AM -0500, Laura Carlson wrote:
 
> We would love to have your input. Please send your comments to this
> thread by May 22. A copy of the draft is also in the Wiki [3].

This proposal is much more consistent with W3C accessibility guidelines,
developed over many years, than the text currently in the HTML 5 draft. As a
result, it is more in line with best practice and policy in organizations that
have adopted the Web Content Accessibility Guidelines, and which, in the
time-frame for the development of HTML 5, will move toward the implementation
of WCAG 2.0, which is now a W3C Candidate Recommendation. It should also be
noted that these guidelines have been incorporated into policy, directly or
indirectly, in a number of jurisdictions, and that future versions of HTML
should be consistent with W3C accessibility guidelines as well as the
practices that have emerged in support of them.

My reservations regarding this proposal are as follows.

It provides much non-normative guidance in the application of the ALT
attribute, which may not be appropriate for inclusion in a markup language
specification, and which moreover could be seen as usurping the role of WCAG
2.0 and its techniques documents. A format specification is not a tutorial.
Nevertheless, there is a legitimate role for non-normative explanations in
clarifying the normative content. I think the discussion in this case should
be confined to a concise description, consistent with WCAG 2.0, of the
function of @alt, a brief discussion of the various possibilities as outlined
in WCAG 2, guideline 1.1, and a reference to that specification and its
techniques for further details.

Much attention has been paid to the syntactic question of whether @alt should
be a required attribute. Ultimately, this depends on the question of what
validating implementations of HTML 5 should treat as correct - what kinds of
errors should be flagged by validators, whether operating as stand-alone
applications or in authoring tools. Given the HTML 5 approach to error
handling in user agents, it seems that regardless of how the syntactic issue
surrounding @alt is decided, the specification will need to define graceful
error handling behaviour, to be consistently implemented by user agents, in
the case of a missing @alt. The present proposal does not address this
issue.

I think it would be helpful if the working group were to clarify, as a
preliminary to addressing the syntactic issue of whether @alt should be
mandatory, the role of validating implementations and the extent to which
validity requirements should be designed to encourage, and to identify
possible departures from, good authoring practices, including practices
required by other W3C specifications such as WCAG 2.0. I would also suggest
that consideration be given to the possibility of multiple levels of
validation, of distinguishing, for example, fatal errors from warnings, as
compilers do in parsing source code. It should also be borne in mind that
accessibility-related validators play an important role in assuring
conformance to those aspects of WCAG 2.0 that are testable at a syntactic
level, and in notifying authors of potentially non-conforming content. Perhaps
there needs to be a broader specification covering HTML validation that would
encompass internationalization, accessibility and other authorial best
practices, identifying aspects which can be tested by syntax alone and the
kinds of warnings or errors that should be given in each case. These
requirements would also apply to code generators and other authoring tools
which impose syntactic constraints beyond those required for HTML parsing, on
the document instances that they produce.
Received on Tuesday, 13 May 2008 01:19:29 GMT

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