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Re: ISSUE-30 longdesc - Chairs Solicit Alternate Proposals or Counter-Proposals

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Sat, 18 Jun 2011 15:23:51 +0200
To: Laura Carlson <laura.lee.carlson@gmail.com>
Cc: HTML WG <public-html@w3.org>
Message-ID: <20110618152351414261.94aa143f@xn--mlform-iua.no>
Laura Carlson, Fri, 17 Jun 2011 13:27:55 -0500:
> On 6/16/11, Charles McCathieNevile rote:
>> On Thu, 16 Jun 2011 17:54:07 +0200, Matthew Turvey wrote:
>> 
>>> WebAIM recommends using a duplicate link if using
>>> longdesc. Longdesc is not available to all users, so you cannot rely
>>> on it to deliver a "a reliable and effective user experience."
>> 
>> I understand the recommendation for a duplicate link.
> 
> Yes. In other words, redundant link text attempts to mitigate damages
> of user agents that do not yet have a long description feature built
> directly into them. Because longdesc it is not yet supported by some
> web browsers, some sites provide a fallback method of providing a full
> description via redundant link text. 

D-link duplication is demotivating, though. Not so much the fact that 
*data* is duplicated as for the fact that it *only* hurts those users 
that *do* use an AT that *do* support @longdesc: It is only that group 
of users that are presented with the link twice, once as longdesc and 
once "heuristically" (or "stumbled upon in the text").

That said: as it stands, to use @aria-describedby instead, would cause 
the link (text) to be read twice even without data duplication: once 
when referenced from aria-describedby and once "heuristically" (or 
"stumbled upon in the text").

> With proper implementation in
> user agents these could all be solely longdesc. In addition, these
> types of link text approaches don't semantically or programmatically
> tie the description to image, whereas a longdesc does.

For @aria-describedby, if it points to a link, then there is a form a 
programmatic tie. However, there is no *semantic* tie. Even if the link 
is presented as link and simply as plain text, it is not possible to 
know *why* the aria-describedby pionts to that link.
-- 
Leif Halvard Silli
Received on Saturday, 18 June 2011 13:24:30 GMT

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