[Bug 9213] New: HTML5 Lacks a Way to Programmatically-Determine Missing Text Alternatives

http://www.w3.org/Bugs/Public/show_bug.cgi?id=9213

           Summary: HTML5 Lacks a Way to Programmatically-Determine Missing
                    Text Alternatives
           Product: HTML WG
           Version: unspecified
          Platform: PC
               URL: http://dev.w3.org/html5/spec/text-level-
                    semantics.html#unknown-images
        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 SECTIONS:

Images whose contents are not known [1]
Guidance for conformance checkers [2] 

BUG DESCRIPTION:

HTML5 Lacks a way to programmatically determine [3] where images whose contents
are not known to be detected and labeled as such. Consider creating a "missing"
attribute.

OUTCOMES OF FIXING THE BUG:

* A "missing" attribute would provide a practical method of detection,
handling, and future improvement. 

* Possibilities for crowdsourcing exist with the addition of a "missing"
attribute It should be reasonably easy to maintain a hash of images with
@missing and the obtain value(s) submitted for them. We would need a canonical
URI (or in HTML5, an 'origin') for the document and an ID for the image, but if
we had a service (either local or remote) that accepted the URI and its @alt
value, then users of AT could associate the values as needed. The worst case is
that nothing is returned. (The second-worst case is that it's a bogus value,
but the owner of the document could manage submitted @alt content.) The pointer
to where to send this information could be in a <link> element, and it could be
a standard HTTP request, or a transaction using the HTML5 Database object. It
could be hosted locally, or by a third party. This idea would get around one of
the biggest problems with around images: that we can see something is wrong
with someone else's content, but can't do anything about it. With this method
people who know what they're doing could directly impact the accessibility of
another organization's content. It also helps image gallery sites since the
image creator or anyone who views the image could propose usable @alt with an
extremely low-bandwidth solution. If this method is used then we'd have to
specify @missing, and that any image with that attribute also needs an ID, or
they wouldn't be associable by the UA/AT. Then we'd need to specify the @rel
attribute for the <link> to the mechanism for associating the @alt. 

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

ATTRIBUTE NAME:

If it is not too long, "notextalternative" could be a suitable name instead of
"missing" for this attribute. The image could be missing any one of text
alternatives in the set of valid options for conformance checkers. 

REFERENCES:

http://dev.w3.org/html5/spec/text-level-semantics.html#unknown-images [1]
http://dev.w3.org/html5/spec/text-level-semantics.html#guidance-for-conformance-checkers
[2]
http://www.w3.org/TR/UNDERSTANDING-WCAG20/conformance.html#uc-programmatically-determined-head
[3]
http://www.w3.org/2009/06/Text-Alternatives-in-HTML5 [4] 


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 16:39:46 UTC