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[Bug 9218] New: Enable Automatic Validators to Programmatically Determine the Presence or Absence of a Set of Text Alternatives

From: <bugzilla@wiggum.w3.org>
Date: Mon, 08 Mar 2010 16:44:21 +0000
To: public-html-a11y@w3.org
Message-ID: <bug-9218-3290@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=9218

           Summary: Enable Automatic Validators to Programmatically
                    Determine the Presence or Absence of a Set of Text
                    Alternatives
           Product: HTML WG
           Version: unspecified
          Platform: PC
               URL: http://dev.w3.org/html5/spec/text-level-
                    semantics.html#guidance-for-conformance-checkers
        OS/Version: All
            Status: NEW
          Keywords: a11y, a11y_text-alt
          Severity: normal
          Priority: P2
         Component: HTML5 spec bugs
        AssignedTo: dave.null@w3.org
        ReportedBy: laura.lee.carlson@gmail.com
         QAContact: public-html-bugzilla@w3.org
                CC: ian@hixie.ch, mike@w3.org, public-html@w3.org, public-
                    html-a11y@w3.org
        Depends on: 8171


SPEC SECTION: Image Guidance for conformance checkers [1] 

BUG DESCRIPTION:

Enable automatic validators to programmatically determine [2] the presence or
absence of text alternatives as HTML4 did with alt. Ensure the set of options
has no loopholes.

Please see an example set [3].

OUTCOMES OF FIXING THE BUG:

1. This will help ensure that images have complete structure. Complete
structure requires both src and text alternatives.

src is to sighted users as text alternatives are to some users with
disabilities.

* Omit the src attribute and sighted users have no content.
* Omit text alternatives and some users with disabilities have no content. 

Without both a src and a text alternative the <img> element is incomplete.

2. Would be in accord with Accessibility Coordination Group's "Consensus
Resolutions on Text alternatives in HTML 5". [4]

3. Enabling automatic validators to programmatically detect the presence or
absence of text alternatives encourages authors to do the right thing.

As the HTML5 editor has said, "we _should_ be calling authors out on this kind
of mistake. Just because people do something doesn't mean we should make it
valid - after all, we made invalid, along with many other things. Conformance
is about trying to advise authors to do the right thing." [5]

4. Requiring a set of programmatically valid options aids in accessibility
education [6]. When the validator flags missing text alternatives it creates a
teachable moment. A moment of great opportunity: a time to flag errors,
educate, to make people aware, and to get action, to get people to actually fix
their pages. The W3C validator is currently used as a web accessibility
teaching tool. Students are instructed to use the W3C validator in classes in
order to flag missing text alternatives. It is the very first step in getting
that important message across. One of their first lessons is to validate HTML
on the W3C site to be sure that it is error-free and that they have indeed
examined each image. It makes a BIG impression that text alternatives are
mandatory not just for WCAG but as well for valid HTML.

REFERENCES

http://dev.w3.org/html5/spec/text-level-semantics.html#guidance-for-conformance-checkers
[1]
http://www.w3.org/TR/UNDERSTANDING-WCAG20/conformance.html#uc-programmatically-determined-head
[2]
http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126#With_Suggested_Text
[3]
http://www.w3.org/2009/06/Text-Alternatives-in-HTML5 [4]
http://www.w3.org/Bugs/Public/show_bug.cgi?id=8000#c1 [5]
http://validator.w3.org/docs/why.html#learning [6] 

HTML5 ISSUE AND CHANGE PROPOSAL:

This is associated with HTML TRACKER ISSUE-31 
http://www.w3.org/html/wg/tracker/issues/31

Change Proposal: Replace img Guidance for Conformance Checkers:
http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126


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Received on Monday, 8 March 2010 16:44:24 GMT

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