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RE: FW: longdesc extension question

From: Andrew Kirkpatrick <akirkpat@adobe.com>
Date: Wed, 28 Aug 2013 15:56:09 +0000
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
CC: "public-html-a11y@w3.org" <public-html-a11y@w3.org>
Message-ID: <EE43A638A0C5E34E80AF78EFE940FC2C10B98ECF6B@nambx09.corp.adobe.com>
Sure.  But as it is sometimes necessary or beneficial to reference an external file or to take advantage of existing support for longdesc where aria support is still growing, longdesc is still useful.  Useful, albeit imperfect, which is the basis for my comment on the Longdesc extension spec.


Andrew Kirkpatrick
Group Product Manager, Accessibility
Adobe Systems


From: Silvia Pfeiffer [mailto:silviapfeiffer1@gmail.com]
Sent: Tuesday, August 27, 2013 7:16 PM
To: Andrew Kirkpatrick
Cc: public-html-a11y@w3.org
Subject: Re: FW: longdesc extension question

Isn't that functionality provided by aria-describedby ?

On Sat, Aug 24, 2013 at 2:09 AM, Andrew Kirkpatrick <akirkpat@adobe.com<mailto:akirkpat@adobe.com>> wrote:
Forwarding to HTML A11Y TF per Chaals's suggestion.


Andrew Kirkpatrick
Group Product Manager, Accessibility
Adobe Systems


-----Original Message-----
From: Charles McCathie Nevile [mailto:chaals@yandex-team.ru<mailto:chaals@yandex-team.ru>]
Sent: Thursday, August 22, 2013 6:00 AM
To: Andrew Kirkpatrick
Subject: Re: longdesc extension question

Hi Andrew

(this is a good question, and I would love to have it in public - feel free to forward my response...)

On Wed, 21 Aug 2013 00:57:54 +0500, Andrew Kirkpatrick <akirkpat@adobe.com<mailto:akirkpat@adobe.com>> wrote:

> Hi Chaals,
> I'm looking at the longdesc extension and also a couple of the WCAG
> techniques and have a question.  It seems that a key problem with the
> implementations of longdesc today (well, at least JAWS and NVDA) is
> that when you activate the longdesc feature for an image they load the
> page with the longdesc and start reading at the required place.  As
> some people are advocating for same-page references or many longdesc
> descriptions on a single separate page this is a problem because JAWS
> and NVDA don't know where the longdesc stops, just where it starts. As
> a result, a user listening to the longdesc for all three images in the
> following example would hear information about "a" once, "b" twice,
> and "c" three times.
> So the question is:  Is there anything in the spec that requires that
> user agents read only the content contained within the HTML object
> with the matching id reference?

No, but there is a "should" requirement on authors:

'Authors should put descriptions within an element which is the target of a fragment link (e.g. longdesc="example.html#description") if a description is only part of the target document.'

which is intended to allow for such behaviour.

In general the spec tries to go lightly on requirements for user agents - it was somewhat controversial to require that they actually make the longdesc available to users in the first place ;(



> Sample.html
> <img alt="a" longdesc="descs.html#a">
> <img alt="b" longdesc="descs.html#b">
> <img alt="c" longdesc="descs.html#c">
> Descs.html
> <div id="a"><p>This is my longdesc for a</p></div> <div id="b"><p>This
> is my longdesc for b</p></div> <div id="c"><p>This is my longdesc for
> c</p></div>
> Thanks,
> Andrew Kirkpatrick
> Group Product Manager, Accessibility
> Adobe Systems
> akirkpat@adobe.com<mailto:akirkpat@adobe.com><mailto:akirkpatrick@adobe.com<mailto:akirkpatrick@adobe.com>>
> http://twitter.com/awkawk
> http://blogs.adobe.com/accessibility

Charles McCathie Nevile - Consultant (web standards) CTO Office, Yandex
       chaals@yandex-team.ru<mailto:chaals@yandex-team.ru>         Find more at http://yandex.com
Received on Tuesday, 3 September 2013 20:39:04 UTC

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