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Re: False aria-describedby expectations in ARIA Authoring Practices (longdesc)

From: Steve Faulkner <faulkner.steve@gmail.com>
Date: Fri, 22 Apr 2011 20:22:40 +0100
Message-ID: <BANLkTim=FPwc2vUHw+qsNWDPDmCycLV1ZA@mail.gmail.com>
To: Jonas Sicking <jonas@sicking.cc>
Cc: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>, Michael Cooper <cooper@w3.org>, Joseph Scheuhammer <clown@alum.mit.edu>, W3C WAI-XTECH <wai-xtech@w3.org>, HTMLwg <public-html@w3.org>, Richard Schwerdtfeger <schwer@us.ibm.com>, David Bolter <dbolter@mozilla.com>
Hi again, it may also be useful to review the aria implementation guide:

5.6.1. Name and Description
http://www.w3.org/WAI/PF/aria-implementation/#mapping_additional_nd

regards
stevef

On 22 April 2011 20:13, Steve Faulkner <faulkner.steve@gmail.com> wrote:
> hi jonas,
> adding rich and d bolter as they may have some useful input.
>
> I suppose it is not so much that people want to restrict it, but how
> all browsers (as in firefox etc) have implemented describedby.
>
> i.e describedby doesn't work the way it is wirtten in the author
> guide. the way it is implemented is that the text content of any
> elements referenced are used as the value for the acc description
> property in accessibility APIs this is a property that can only take
> plain text (as far as i know) and the content of which can be accssed
> by AT via the API is just that plain text.
>
> the emerging consensus on providing an aria feature like longdesc (for
> example) is that it will need to be a new feature, not a modified
> describedby.
>
> regards
> stevef
>
>
> On 22 April 2011 19:55, Jonas Sicking <jonas@sicking.cc> wrote:
>> On Thu, Apr 21, 2011 at 7:26 PM, Leif Halvard Silli
>> <xn--mlform-iua@xn--mlform-iua.no> wrote:
>>> Michael and Joseph,
>>>
>>> Where do we file bugs against your 'WAI-ARIA 1.0 Authoring Practices'
>>> editors draft?
>>>
>>> There is a much erroneous and misleading description of the
>>> possibilities of aria-describedby is in the draft. The draft states
>>> that it is possible to "follow" what you refer to as an
>>> aria-describedby "arc" from an img element to an anchor element - et
>>> cetera: [1]
>>>
>>> ]] ... different from the HTML longdesc attribute ... But if you wish
>>> to reference an external resource with aria-describedby, you can
>>> reference a link that in turn references the external resource. This
>>> requires the user to follow two steps, first following the
>>> aria-describedby arc, then following the link, but does address the use
>>> case. [[
>>>
>>> However, this is an incorrect description of the facts:
>>> aria-describedby doesn't allow you to "follow" the aria-describedby as
>>> if it was a link. Besides that it is technically wrong, the example you
>>> show leads to repetition for the user: first the textual content of
>>> that anchor element is read to the user when he/she reads the img
>>> element (without being told that it is a link nor be given opportunity
>>> to link to it). And when the screenreader user reaches that link,
>>> he/she gets to listen to the same link text again.
>>>
>>> Your claims in the draft is already being repeated in the wild. [2]
>>> Which seems entirely useless: In the HTMLwg, we've established (for the
>>> last time) one month before your last edition of the draft that
>>> aria-describedby does not have any such functionality. (I provide two
>>> of several possible links. [3][4]) The only thing that happens if one
>>> points aria-describedby to an anchor element is that the user is served
>>> the textual content of that link, without being whether taken to that
>>> link or being told that he/she listens to the text of the link.
>>>
>>> Please remove those false claims ASAP.
>>>
>>> [1] http://www.w3.org/WAI/PF/aria-practices/#Descriptions_external
>>> [2] http://rebuildingtheweb.com/en/longdesc-replacement/#c20110420054615
>>> [3] http://www.w3.org/Bugs/Public/show_bug.cgi?id=12243
>>> [4] http://lists.w3.org/Archives/Public/public-html-a11y/2011Mar/0166
>>
>> Actually, I don't think we have established that ARIA can't be used in
>> this way. Back when I wrote my comment in bug 12243 I had taken at
>> face value several comments on this list the claim that
>> aria-describedby only represents a reference to the textual contents
>> of whatever elements it points to.
>>
>> However once I looked at the spec I found no such requirements of
>> limiting the reference to the textual contents. It seems to me that
>> ARIA simply says that a description of the element can be found in the
>> referenced elements. I see neither any reason nor requirements to
>> remove the semantics of those referenced elements when reading the
>> contents to the user.
>>
>> I've since asked for why people feel like there is a need to restrict
>> to textual contents when following aria-describedby, but so far have
>> not received an answer. So consider this me asking again :)
>>
>> / Jonas
>>
>>
>
>
>
> --
> with regards
>
> Steve Faulkner
> Technical Director - TPG
>
> www.paciellogroup.com | www.HTML5accessibility.com |
> www.twitter.com/stevefaulkner
> HTML5: Techniques for providing useful text alternatives -
> dev.w3.org/html5/alt-techniques/
> Web Accessibility Toolbar - www.paciellogroup.com/resources/wat-ie-about.html
>



-- 
with regards

Steve Faulkner
Technical Director - TPG

www.paciellogroup.com | www.HTML5accessibility.com |
www.twitter.com/stevefaulkner
HTML5: Techniques for providing useful text alternatives -
dev.w3.org/html5/alt-techniques/
Web Accessibility Toolbar - www.paciellogroup.com/resources/wat-ie-about.html
Received on Friday, 22 April 2011 19:23:27 GMT

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