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Re: ISSUE-30 (Longdesc) Change Proposal

From: Jonas Sicking <jonas@sicking.cc>
Date: Wed, 28 Oct 2009 23:29:52 -0700
Message-ID: <63df84f0910282329s4b1df8a1vfa9fe15a7310e3ad@mail.gmail.com>
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Cc: Charles McCathieNevile <chaals@opera.com>, "public-html@w3.org" <public-html@w3.org>
On Wed, Oct 28, 2009 at 6:19 PM, Leif Halvard Silli
<xn--mlform-iua@xn--mlform-iua.no> wrote:
> Jonas Sicking On 09-10-29 00.57:
>
>> On Wed, Oct 28, 2009 at 7:59 AM, Leif Halvard Silli:
>>>
>>> Jonas Sicking On 09-10-27 20.15:
>>>>
>>>> On Tue, Oct 27, 2009 at 7:09 AM, Leif Halvard Silli:
>>>
>>>>>> I agree that @longdesc and @aria-describedby aren't exactly the same.
>>>>>> However they are very similar.
>>>>>
>>>>> Everything with a link is "similar". But normally, if one element can
>>>>> take
>>>>> IDREFS only and another can take a single, complete URI, only, then we
>>>>> don't
>>>>> consider them similar.
>>>>
>>>> If two features are designed to solve the same problem, then I think
>>>> they are similar enough that having both is a loss for all involved
>>>> parties.
>>>
>>> I think you should try to put in words what the "same problem" is. It
>>> sounds
>>> to me as if the only sameness you have in mind is "accessibility". That
>>> is a
>>> MUCH too wide sameness.
>>>
>>> Fact is: @alt and @aria-labelledby are somewhat related [*]. Why don't
>>> you
>>> propose to remove the one or the other?
>>
>> If @alt was used as little as @longdesc is then I would definitely
>> propose to remove @alt as well.
>>
>> Removing @alt at this point would break a lot of existing content out
>> there.
>
>
> It would not break anything: "removing" as per HTML 5 means that authors
> should not use the feature anymore, but that user agents continue to
> implement it.

True, depends on how we "remove" it, and what you mean by "break". See
more below.

>> That's the only reason why I think we should not let
>> @aria-describedby replace @alt.
>
> Ahem ... Either you did not notice that I spoke about aria-LABELLEDBY.  Or,
> you are saying that you would like aria-DESCRIBEDBY to replace
> aria-LABELLEDBY ... Aria-describedby is not a solution to everything ...
>
> For the record, "@aria-label" (not @aria-labelledby) is what is equal to
> @alt. But since HTML has @alt, we don't use aria-label (on IMG at least).

Ok, point taken. I don't actually know enough about accessibility to
say if aria-label and/or aria-describedby could replace alt. Reading
the spec it actually doesn't seem like either does. It says regarding
labels:

"A label should provide the user with the essence of what the object does"

And regarding descriptions:

"a description is intended to provide detail that some users might need"

However neither seems to describe @alt. Both the HTML4 spec, and the
implementations I know, treat @alt as fallback content:

"alternate text to serve as content when the element cannot be
rendered normally"

So if I have an image that contains a fancy rendering of a headline,
the @alt attribute would contain the actual text of that headline.
However it doesn't seem appropriate to put the text of the headline in
neither an aria label or an aria description.

Ultimately I still think that removing @alt at this point is bad,
irrelevant of if there is a collision with aria features or not. There
simply is too much content out there that uses it. Asking all the
authors that filled out an alt attribute would not make us any
friends.

There's another good reason too which I forgot to mention in my
previous email, but which I've mentioned on this list before. @alt is
one of very few success stories for accessibility-specific features.
There's more correctly authored @alt attributes out there than
@longdesc, @summary, @headers and @aria-* put together. Messing with
@alt would be trying to fix something that isn't broken.

The same can not be said for @longdesc and @summary, neither of which
has seen any significant amount of real-world uptake. Yes, there is
more than zero uptake, but I don't think there is enough to warrant
having duplicate (or near-duplicate) features.

/ Jonas
Received on Thursday, 29 October 2009 06:30:52 GMT

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