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Bug 9218 - Enable Automatic Validators to Programmatically Determine the Presence or Absence of a Set of Text Alternatives
Summary: Enable Automatic Validators to Programmatically Determine the Presence or Abs...
Status: CLOSED DUPLICATE of bug 8716
Alias: None
Product: HTML WG
Classification: Unclassified
Component: pre-LC1 HTML5 spec (editor: Ian Hickson) (show other bugs)
Version: unspecified
Hardware: PC All
: P1 normal
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: HTML WG Bugzilla archive list
URL: http://dev.w3.org/html5/spec/text-lev...
Whiteboard:
Keywords: a11y, a11y_text-alt
Depends on:
Blocks:
 
Reported: 2010-03-08 16:44 UTC by Laura Carlson
Modified: 2011-01-01 21:51 UTC (History)
7 users (show)

See Also:

Attachments

Description Laura Carlson 2010-03-08 16:44:21 UTC 
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
Comment 1 Maciej Stachowiak 2010-03-23 06:20:56 UTC 
Requesting expedited processing of this bug on behalf of the HTML WG.
Comment 2 Ian 'Hixie' Hickson 2010-03-23 09:49:45 UTC 
I have no idea what this is asking for. Can someone summarise the request in simple English? What is the problem that the spec doesn't solve?
Comment 3 Maciej Stachowiak 2010-03-23 09:59:34 UTC 
(In reply to comment #2)
> I have no idea what this is asking for. Can someone summarise the request in
> simple English? What is the problem that the spec doesn't solve?
> 

I think the request is to make sure the validator will report an error if an image does not have alt, and also does not have one of the allowed alternative ways to provide replacement text or express that there isn't any. However, I think the spec already does this. Therefore I suspect this bug should be a WORKSFORME resolution.

In email to Laura I said:
----------------------

As far as I can tell, the text here requires validators to report an error if alt is absent and none of the conditions applies:
http://dev.w3.org/html5/spec/Overview.html#guidance-for-conformance-checkers

"A conformance checker must report the lack of an alt attribute as an error unless one of the conditions listed below applies:..."

That seems equivalent to me to what is in your Change Proposal. You have a slightly different set of conditions, but I do not see how your set is more programmatically checkable than the one currently in the draft.
Comment 4 Laura Carlson 2010-03-23 15:46:06 UTC 
I see your point, Maciej. I'll mark this bug as a duplicate of 8716 as that is the main bug for change proposal.
http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126

*** This bug has been marked as a duplicate of bug 8716 ***
Comment 5 Martin Kliehm 2010-12-07 16:30:02 UTC 
The bug-triage sub-team thinks since this is a duplicate it's not accessibility task force priority.