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Re: [XHTML2] Specifying alternative resources/content

From: Risto Kankkunen <risto.kankkunen@iki.fi>
Date: Mon, 18 Oct 2004 20:32:45 +0300
Message-ID: <4173FE3D.2010606@iki.fi>
To: Edward Lass <elass@goer.state.ny.us>
CC: www-html@w3.org

Thanks for your comments, Edward. Here's a quick reply to one of your 
comments:

> One of your examples is this:
> 
>    <alt>
>        <!-- Try to show a video clip -->
>        <object
>            src="holiday.mpeg"
>            type="video/mpeg"
>        </
> 
>        <!-- Or show a still image and audio -->
>        <div>
>            <object src="holiday.jpeg" type="image/jpeg" />
>            <object src="holiday-narration.mp3" type="audio/mp3" />
>        </div>
> 
>        <!-- Or show an image and some text -->
>        <div>
>            <object src="holiday.jpeg" type="image/jpeg" />
>            <p>Our holiday started on Sunday, the 1st of August. ...</p>
>        </div>
> 
>        <!-- Or show just a place holder -->
>        <p>(holiday picture here)</p>
>    </alt>
> 
> Now this is how one could do it under the current WD:
> 
> <!-- Try to show a video clip -->
> <object src="holiday.mpeg" type="video/mpeg">
> 
> 	<!-- Else, show a still image and audio -->
> 
> 	<object src="holiday.jpeg" type="image/jpeg">
> 
>  	       <!-- If the image doesn't work, show just a place holder -->
> 	       <p>(holiday picture here)</p>
> 
> 	</object>
> 
> 	<object src="holiday-narration.mp3" type="audio/mp3">
> 
> 		<!-- If the audio doesn't work, show text -->
> 		<p>Our holiday started on Sunday, the 1st of August. ...</p>
> 
> 	</object>
> </object>

That's different! Using my "<alt>" notation that would be:

   <alt>
       <!-- Try to show a video clip -->
       <object src="holiday.mpeg" type="video/mpeg" />

       <!-- Else, show a still image and audio -->

       <alt>
  	  <object src="holiday.jpeg" type="image/jpeg" />
           <!-- If the image doesn't work, show just a place holder  -->
  	  <p>(holiday picture here)</p>
       </alt>

       <alt>
           <object src="holiday-narration.mp3" type="audio/mp3" />

           <!-- If the audio doesn't work, show text -->
           <p>Our holiday started on Sunday, the 1st of August. ...</p>
       </alt>
   </alt>

> In the proposal above, the user agent has to look inside the <div/>
 > element, and if it reports that it can accept JPEG but not MP3, it
 > has to reject that block altogether and go to the next one?

Right.

The whole point of the example was that with "<alt>" you COULD combine 
related resources so that they all have to be available for a meaningful 
presentation or another alternative should be tried. But you don't of 
course have to do that, if you don't want.

The mechanism of the draft doesn't have this opportunity at all.

(My example should have been better, e.g. with unique images so that you 
cannot optimize the common part out of the equation...)


Regards,
Risto Kankkunen
Received on Monday, 18 October 2004 17:32:40 GMT

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