Monday, June 11, 2012

Image alt Exception Change Re-Re-Requested

HTML5 logo — I am the 'alt,' not the 'title' Just over a year ago now I covered how the HTML5 specification is going to allow the alt attribute to be excluded from img elements under some very specific circumstances (Image alt Attributes Not Always Required in HTML5 and More on Image alt Requirement in HTML5).

The one I am covering today is that the presence of a meta name=generator element, which implies the HTML was generated by some sort of WYSIWYG editor or automated tool, makes the absence of an alt attribute valid.

The motivation here seems to be about making it easier for developers and authoring tools to get pages to validate — but to the detriment of accessibility. Whereas failed validation due to a missing alt can be a clue to a less technical page author (including WYSIWYG users) that something needs to be done, giving a free pass to pages generated from WYSIWYG editors means that authors won't be alerted and therefore are likely to make image content inaccessible.

When comparing the two options (ease of validation versus accessibility for users with disabilities), there doesn't seem to be a complex argument required to make the change. That is not the case, however.

Late last week the latest change request (Issue 31c Meta Generator Updated) was handed in for removing the meta name=generator exception. If you look at the table of contents you can see that it has been batted down twice before, though without addressing all the points raised. This of course left the meta name=generator exception open to be challenged again.

Each of the nine core arguments has been updated and two more have been added:

  1. Fixing something bad by introducing a document-global switch is a Bad Idea (new)
  2. "Legacy use" of meta generator is never likely to be supplanted by use conforming to the current spec text (new)
  3. Inadvertently and retroactively introducing new, undocumented, magic semantics (minor update)
  4. Fatal ambiguity in the specification (minor update)
  5. Tool-mediated insertions of alternative text are ignored (minor update)
  6. The "generator exception" obviates the intent of the Validator (updated)
  7. The "generator exception" results in inequitable rendering of graphical content (updated)
  8. The "generator exception" breaks harmonization with other standards and guidelines (updated)
  9. The "generator exception" inappropriately gives authoring tool conformance considerations precedence over end-user requirements (updated)
  10. Harmful consequences of the generator exception include harm to web authors and to web content users with disabilities (updated)
  11. The weighting of objections against the "generator exception" is opaque (updated)

It's a hefty read. If you already agree that the meta name=generator exception is a bad idea, then you probably don't need to read through it. If you are unsure or want to know, then the detail is good. Sadly, the previous rejections mean that so much detail has been tossed in here that it's not an easy read.

Even if you don't care for all the detail, the statement of impact at the end should be enough to convince you that it's kind of an easy decision:

Positive Effects

  • Authors can more safely assume that when they use a validator it will appropriately check the conformance of the document, rather than some arbitrary subset of requirements.
  • The use of meta name=generator will not change in a way that is contrary to its current usage and effects.
  • Authors will be made aware that they have not provided a text alternative giving them the opportunity to fix their error and produce a conforming document.
  • Upholds the structural integrity of <img> element.
  • Enables automatic validators to programmatically detect occurrences of the presence or absence of text alternatives. Bug 9218.
  • Facilitates accessibility awareness and education.
  • Upholds the HTML section 3.2. "Priority of Constituencies" Design Principle.

Negative Effects

  • None

Raising a stink about this on your blogs, in your tweets, and (ideally) face-to-face with anyone from the HTML Working Group might mean that the third time is the charm.

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