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RE: Issue 203 Change Proposal

From: John Foliot <john@foliot.ca>
Date: Thu, 26 Apr 2012 21:39:21 -0700
To: "'Silvia Pfeiffer'" <silviapfeiffer1@gmail.com>
Cc: "'HTML Accessibility Task Force'" <public-html-a11y@w3.org>
Message-ID: <05ed01cd242f$b9fc6080$2df52180$@ca>
Silvia Pfeiffer wrote:
> 
> Hi John,
> 
> I don't understand your objection to aria-label. You write:
> 
> "Unlike other methods of supplying a short label to the media elements
> (for example aria-label), using @alt will (MUST) render text on screen
> when images are turned off or disabled."
> 
> Nothing in the definition of aria-label [1] excludes the aria-label
> text from being rendered as replacement text for video or audio. Do
> you have evidence of such happening?.  

Nothing about aria-label suggests that it should be rendered as on-screen
text either; in fact aria-label is mapped to the accessibility APIs, and
there is no instance of any user-agent rendering the aria-label string as
on-screen text that I am aware of, and no indication by any browser that
this will change any time soon. In fact, if it were to be on-screen, you
would use aria-labelledby instead.

I discussed this at length with Rich today, and in the end he agreed that
there was a specific use-case for @alt that was not being met with either of
the aria-label or aria-labeleddby attributes - he actually helped me write
the proposed spec text found in my CP.

If the user has disabled or "turned off" images (say for performance
reasons) then the browsers render the @alt text on screen as "fallback". At
first Rich asked why not just use the fallback content inside of
<video>fallback</video> - except that often times that might in fact be
embedded flash, which when images are disabled should also be disabled.
Other times it might be a message "This browser does not support HTML5
Video" even though it may in fact do so, it's just that the current
configuration is not rendering images (et al) for performance reasons
(user-choice). Finally, even the current spec notes that this fallback
content is not to be used for accessibility accommodations. We need a text
replacement here that aria-label cannot provide, as aria-label does not
render on screen.

JF
Received on Friday, 27 April 2012 04:39:54 GMT

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