Enable Automatic Validators to Programmatically Determine the Presence or Absence of a Set of Text Alternatives

Bug Number

9218

Bug Title

Enable Automatic Validators to Programmatically Determine the Presence or Absence of a Set of Text Alternatives

Spec Section

• 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.

http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126