[html4all] Object element support

[Jason White]

On Tue, Aug 19, 2008 at 01:45:11PM +0200, Leif Halvard Silli wrote:
 
> That might be. But if so, then it seems to that it is a bug which 
> has turned out to become a feature.

I'm not persuaded that it is a feature. Personally, I don't care about the
distinction between "short" and "long" alternatives, but only that there is an
alternative that adequately substitutes for the image.
> 
> > Of course, if the author so desires, the alternative can
> > include a link referring to additional information. This is
> > true of OBJECT as well:
> > 
> > <object data="image"><p>An image. <a
> > href="description.html">See this description for full
> > details.</a></object>
> 
> 
> That to me is not different from
> 
> 	<p><img src=src alt="" />
> 	Short.
>          <a href=longDescription >Long.
> 	</a></p>
> 
>  
> 
> (But then, why would be need @longdesc?)

The two cases are very different. In the OBJECT case, the fact that the link
is contained in the OBJECT element establishes that it is part of the
alternative to the image. In your IMG example, the link is not, and cannot be,
included in the IMG element without the use of @longdesc. Hence, the image and
the link are semantically unrelated so far as the markup is concerned,
whereas, by definition, the content of the OBJECT element serves as an
alternative to the resource referred to in @data.
 
> > However, assuming that this is considered a 
> > problem worth addressing, I can think of several alternative
> > solutions:
> > 
> > a. To define the semantics of @title on OBJECT as serving the
> > purpose of providing a short alternative.
> 
> Why would that be better than adding @longdesc to OBJECT?

OBJECT already supports block-level content. The only reason for creating
@longdesc in the first place was that IMG didn't support inline or block-level
content. Since OBJECT doesn't have this design shortcoming, there is no need
for @longdesc, and including it would create a lot of confusion regarding how
to treat block-level content vs. the resource referred to by @longdesc.
> 
> > c. To define <a rel="alternative"> so that the link can be
> > identified as a long alternative to the object.
> 
> 
> For use inside Object? Like this:
> 
> 	<object image=data>Short.
> 	<a href=long rel=alternative>Link
> 	</a></object>
> 
>  
> 
> Then you are also saying that the first fallback is naturally short.

No, this is precisely what I am not saying. The fallback can be inline or
block-level, and as long as the author wishes it to be. However, if the author
wants to provide only a brief alternative in the text as a substitute for the
image, and more detail separately which the user can access, then it is
possible to do so by means of a link.

The IMG element forces a distinction between "short" and "long" alternatives.
OBJECT has the advantage, in its design, of not doing so. If I want to provide
a table as an alternative to a chart, I can do so without having to create a
separate page and using a link or @longdesc, provided that I use OBJECT rather
than IMG.

This is an advantage of OBJECT over IMG, and has long been acknowledged as
such.