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Re: unifying alternate content across embedded content element types

From: Sander Tekelenburg <st@isoc.nl>
Date: Fri, 13 Jul 2007 17:44:31 +0200
Message-Id: <p06240627c2bd3e36552e@[192.168.0.102]>
To: <public-html@w3.org>

At 17:26 -0500 UTC, on 2007-07-06, Robert Burns wrote:

> On Jul 6, 2007, at 3:31 PM, Sander Tekelenburg wrote:

[...]

> The @alt attribute is
> only available for <img>. Is it just because @longdesc is so
> difficult to work with?

As someone else explained, @alt is available only for <img> because <img> is
an empty element and thus needed to have some mechanism added to it to be
able to provide fallback. As the HTML 4.01 spec says, @alt is for a short,
required, alternative, @longdesc for a longer, non-required, alternative.

> Or are there (now) other reasons to separate
> alternatives into short and brief versus long and richly semantic.
> Because if there are other reasons than perhaps we need to add @alt
> to all the other embedded content elements too.

I'm not aware of other reasons for @alt to exist than <img> being empty.
Which other elements would need @alt? Non-empty tags, such as <object>, allow
for rich fallback. Why would you want to impoverish that?

> To reiterate the list of alternate information available for non-text
> media:
>
> 1) media-file-specific fallback content / accessibility hooks /
> textual metadata
> 2) the surrounding prose
> 3) the <legend>
> 4) alternate (fallback) content
> 	a)  the rich fallback (sometimes through @longdesc otherwise through
> the element's contents)
> 	b) @alt (currently on <img> only)
> 	c) @title (on everything embedded)

I still have absolutely no idea why you list @title as a mechanism to provide
an alternate/fallback. That's not at all what HTML 4.01 says about @title and
I don't recall it's ever been different in a previous spec.

[...]

>> Both @alt and @longdesc are about *alternatives*  to the
>> image. @title
>> is for a certain type of *additional* information.
>
> Would you say then that @title, in providing "additional"
> information,, sufficiently fulfills the needs for brief alternate
> description on all of the other embedded content elements (i.e.,
> other than <img>)?

No, because "additional" != "alternate".

> I hope that by taking the opposite tack of my first email, it is
> clearer what I'm trying to say.

Sorry, no, it isn't. I don't understand what makes you say that @title has
anything to do with alternative content/fallback. I don't understand why
you'd say other elements than <img> need @alt. (Maybe you're playing the
devil's advocate, but then still I don't understand what point you're trying
to make.)

> That is I'm not advocating for
> replacing @alt with @title. Rather, I'm trying to unify, as much as
> possible, how we use these various embedded content elements.

My impression is it is all quite unified already. Non-empty elements allow
for rich fallback 'automatically'. <img> is the only exception. I would like
to get rid of that exception exactly because @alt is so poor. One option is
to encourage authors to use <object>, which will require that IE gets fixed.
Another is to add a new element, like <picture>.

Because either solution will still mean <img> remains allowed, I proposed
that @alt and @longdesc are at least improved in HTML5:
<http://esw.w3.org/topic/HTML/LongdescRetention#head-ef01c5377a967ead313aeecea431de086517670a>.


-- 
Sander Tekelenburg
The Web Repair Initiative: <http://webrepair.org/>
Received on Friday, 13 July 2007 15:47:54 GMT

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