W3C home > Mailing lists > Public > public-html-a11y@w3.org > August 2013

Re: FW: longdesc extension question

From: Charles McCathie Nevile <chaals@yandex-team.ru>
Date: Wed, 28 Aug 2013 21:58:20 +0200
To: "Andrew Kirkpatrick" <akirkpat@adobe.com>, "Silvia Pfeiffer" <silviapfeiffer1@gmail.com>
Cc: "public-html-a11y@w3.org" <public-html-a11y@w3.org>
Message-ID: <op.w2jlria8y3oazb@chaals.local>
On Wed, 28 Aug 2013 01:15:37 +0200, Silvia Pfeiffer  
<silviapfeiffer1@gmail.com> wrote:

> Isn't that functionality provided by aria-describedby ?

only in the case where the target of describedby is local to the document.  
Unlike longdesc, aria-describedby cannot support external descriptions.

(The long-term picture is that aria-describedat might be implemented and  
change this, but currently it hasn't happened).

cheers

Chaals

> Silvia.
>
>
>
> On Sat, Aug 24, 2013 at 2:09 AM, Andrew Kirkpatrick  
> <akirkpat@adobe.com>wrote:
>
>> Forwarding to HTML A11Y TF per Chaals's suggestion.
>>
>> Thanks,
>> AWK
>>
>> Andrew Kirkpatrick
>> Group Product Manager, Accessibility
>> Adobe Systems
>>
>> akirkpat@adobe.com
>> http://twitter.com/awkawk
>> http://blogs.adobe.com/accessibility
>>
>>
>> -----Original Message-----
>> From: Charles McCathie Nevile [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>
>> 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 ;(
>>
>> cheers
>>
>> Chaals
>>
>> > 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,
>> > AWK
>> >
>> > Andrew Kirkpatrick
>> > Group Product Manager, Accessibility
>> > Adobe Systems
>> >
>> > akirkpat@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         Find more at http://yandex.com
>>


-- 
Charles McCathie Nevile - Consultant (web standards) CTO Office, Yandex
       chaals@yandex-team.ru         Find more at http://yandex.com
Received on Wednesday, 28 August 2013 19:58:49 UTC

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