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Re: unifying alternate content across embedded content element types

From: Robert Burns <rob@robburns.com>
Date: Fri, 13 Jul 2007 18:46:04 -0500
Message-Id: <27131F1A-913C-4AB6-A20F-8F9B1AC0DC82@robburns.com>
Cc: <public-html@w3.org>
To: Sander Tekelenburg <st@isoc.nl>


On Jul 13, 2007, at 6:34 PM, Sander Tekelenburg wrote:

>
> 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.


I'm not asking about the history of @alt and @longdesc. There's a  
definite block to you understanding what I"m saying. I've tried  
several different ways and I have no more ideas, so I just let it go.  
If anyone else has a suggestion for the log-jam, please join inn the  
conversation.

Take care,
Rob
Received on Friday, 13 July 2007 23:46:13 GMT

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