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Re: unifying alternate content across embedded content element types

From: Sander Tekelenburg <st@isoc.nl>
Date: Sat, 14 Jul 2007 01:34:37 +0200
Message-Id: <p0624062fc2bdb6186e43@[]>
To: <public-html@w3.org>

At 15:04 -0500 UTC, on 2007-07-13, Robert Burns wrote:

> On Jul 13, 2007, at 10:44 AM, Sander Tekelenburg wrote:


>> Non-empty tags, such as  <object>, allow
>> for rich fallback. Why would you want to impoverish that?
> I'm not advocating impoverishing anything. I'm not even sure what
> that  sentence refers to.

That refered to your earlier "perhaps we need to add @alt to all the other
embedded content elements too".


> I list @title because if an author wants to provide <em>short</em>
> descriptive information for a media file on an <object> element
> (i.e., something that would show up in a text-only browser or get
> handled in a non-visual UA), they would need to use @title to do so.

What makes you think that @title is only for text-only/non-visual UAs? It's
for every and any UA. It's nothing to do with fallback.

> However, on an <object> element that provided additional information
> in the @title attribute that would serve as an alternate for media-
> poor UAs.

No it wouldn't. It would serve as addtional[*] information, period.
Additional to either the resource embedded by the object or its fallback
content, regardless of which is presented.

[*] "advisory", according to the spec.


> The <img> element has two separate alternate mechanisms: @alt and
> @longdes. Each has been given separate roles for alternate content:
> @alt short plain-text and @longdesc semantically rich lengthier
> text.  So the question I'm trying to pose is why two on <img> and not
> two on the other embedded content elements (and why none on <embed>)?

I think you're asking about the history of @alt and @londesc. Maybe that can
be dug up in some W3C archive. My assumption is that @alt was added so as to
allow for an inline textual alternative, to be presented *in place of* the
missing image. It was recognised how limiting this is, so @longdesc was
added. @longdesc alone would have the downside that fallback content would
not be available inline, in the flow of the main document. So it cannot
replace @alt. The two are complimentary. Neither can replace the other.

Non-empty elements don't need this mess.

Sander Tekelenburg
The Web Repair Initiative: <http://webrepair.org/>
Received on Friday, 13 July 2007 23:37:53 UTC

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