Monday, May 2, 2011

More on Image alt Requirement in HTML5

HTML5 logo -- I am the 'alt,' not the 'title' Nearly two weeks ago I wrote up a post outlining the W3C decision to no longer require the alt attribute on images in HTML5: Image alt Attributes Not Always Required in HTML5. I was genuinely surprised to see that was the most popular post on this blog and garnered the most re-tweets on Twitter I've ever had.

I pulled the alt decision off the W3C mailing list, before it was officially announced in any forum, so I suspected it might languish in obscurity for a while. I wasn't quite right. First, to recap the decision:

  • The presence of aria-labelledby does not make missing alt conforming.
  • The presence of role=presentation does not make missing alt conforming.
  • The presence of <meta name=generator> makes missing alt conforming.
  • Use of private communications does not, in itself, make missing alt conforming.
  • The presence of title makes missing alt conforming.
  • The presence of figcaption makes missing alt conforming.

Just over a week later, Steve Faulkner, member of W3C HTML Working Group along with other W3C working groups, provided a more in-depth and detailed overview, including a re-hash of the full decision in his post HTML5 Accessibility Chops: the alt decision.

On Friday, the HTML Accessibility Task Force mailing list took up the discussion of the alt attribute, starting in the email with the subject "[text] updated draft of clarification on alt validation." This message outlines the response to the alt decision, specifically targeting those issues with which the Accessibility Task Force has taken issue.

To distill the response on why the exception for the presence of <meta name=generator> should be re-examined (these are just the key points, descriptions of each are in the email):

  • Evidence: deliberately omitting alt due to generator exception.
  • Evidence: list of authoring tools (mis)using the meta generator.
  • Evidence: lack of alt checking is harming:
    • A reintroduction of versioning.
    • Two tier document quality.
    • Generator is already in use for other purposes.
    • Drops all requirements on the floor.
    • Alternatives to the generator exception.

A distilled high-level list of why the presence of a title attribute obviates the need for an alt:

  • Title has taken on the role of a visual element in the form of a tooltip and invisible when images are turned off, but alt is visible when images are turned off.
  • Where images are disabled or inaccessible in current browsers such as smartphones saving bandwidth, title will be useless to users.
  • Title text will now be generated on even decorative images, negatively impacting the user experience.
  • A link to screenshots (IE8, Firefox, Chrome, Opera, Safari) is provided as an example of how a title and alt display when images are disabled.

Finally, on the decision that <figure> with an associated <figcaption> allows the exclusion of alt (also distilled):

  • Given that <figcaption> lends itself to verbose text, this may be far more than is necessary for an end user, and removes the ability for the user to choose.
  • Current use of <figcaption> tends to be for images users can see, whereas alt is for images users cannot see.
  • Screen readers do not currently support <figcaption>, meaning it cannot effectively replace alt today.

Further discussion on this draft is scheduled for a meeting among the W3C HTML Accessibility Task Force today (May 2). In the meantime, feedback has been rolling in from other members on the list, some of them challenging the assertions made in the draft response. You can continue to follow the discussion by reading the thread in the April 2011 mail archive. Since May has just started and this thread crosses into May, you can catch up on the most recent discussion in the May 2011 mail archives.

Sadly, as evidenced by my posting silence for most of April, I won't be able to follow the results of a meeting today and will probably have to wait for the news like everyone else. If this topic interests you , then you may want to follow along on the W3C mailing list archives.

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