[html4all] Object element support

[Leif Halvard Silli]

Robert J Burns 2008-08-21 00.49:

> On Aug 20, 2008, at 3:35 PM, Leif Halvard Silli wrote:


>>      <object data=one-movie.mov >
>>     <!-- all this is fallback for 'one movie': -->
>>      <img src=src alt='Fallback for IMG, as part of
>>         fallback for one-movie.' >
>>      <object  data=another-movie.mov >
>>     Fallback for 'another movie', which again is
>>         fallback for one-movie.
>>         <!-- end of fallback for 'one movie' -->
>>      </p></object></object>
>>
>> But this, then -- again -- illustrates how the fallback of OBJECT
>> isn't geared at screen readers, as the fallback itself can contain
>> both text and movies, simultanously.
> 
> Well it is still geared at screen readers as long as each bit of 
> embedded non-text media has some text fallback. In your example 
> everything is covered in terms of alt text / text equivalents.


So you don't hink a validator should OK this?

>> Must give this more thought. But I feel what you say suppports
>> what I've said about how OBJECT is lacking an actual description
>> of how it, in the "real world", is going to be used. There is to
>> much high level "it is superior" thinking going on, without
>> looking at the details of how it should be used, is my view.
> 
> Yeah, I think you're partially right. I took a look at the HTML 4.01 
> prose[1] and DTD[2] and the DTD fails to give unambiguous normative 
> guidance on precisely how this should work. The prose on the other hand 
> do explain it, but there could still be some ambiguities that I'm 
> missing. It doesn't have the normative language that the HTML5 draft 
> should include. It should be made clear that every object element should 
> include an ultimate fallback object element containing FLOW content 
> minus any other embedded non-text media elements. (IMG, CANVAS, APPLET, 
> EMBED, VIDEO, AUDIO, OBJECT).
>

> I think your example is still a bit unorthodox however, since normally 
> the content model should be (PARAM* , OBJECT) or (PARAM* , (&flow;)* - 
> [embedded media elements]). 


HTML 4 does not preclue the inclusion of IMG amongst the flow 
elemements. In fact, IMG is also flow. As is OBJECT itself. (As 
you yourself note .)

> In other words either object fallback or 
> flow fallback with no embedding. I think the conformance checker should 
> check for this. And in cases other than role='decorative', the 
> conformance checker should throw errors for missing text fallback (or 
> throw warning for role='photo').


Perhaps a warning if the flow contains an IMG. But not an error, 
unless the fallback of the IMG itself is used wrong. Why shouldn't 
embedded not-text elements be permitted,  provided they contain 
fallback themselves?

I also wonder whether <objeect type="text/html" .... > should be 
equal to the requirement of text fallback?

> BTW, further reflection on your earlier quote form the Microsoft IE 
> Blog[3], leaves me a little stunned if this is actually true. Does 
> anyone have IE (any version) handy to test this? As Leif quoted earlier:
> 
> "<OBJECT> is not parsed in a cross-browser compatible way (parsing stops 
> at the OBJECT, whereas other browsers continue parsing all the fallback 
> content and make it available. No support for this parsing behavior is 
> planned for IE8; I'll take this opportunity to ask for real-world 
> scenarios that can help me prioritize this feature."

 >

> I find it hard to believe that the content of the OBJECT element are not 
> parsed. Is it simply thrown away? Is it added to the DOM as plain text? 
> Or does it mean that the more sophisticated fallback mechanism enabled 
> by the OBJECT element is not supported so that IE simply handles only 
> the first embedded content and ignores the remaining content. Does IE 
> have a DOM browser like the other browsers? I guess you could always 
> view it at Hixie's DOM viewer[4]. If the tree of OBJECT elements is 
> shown properly nested with the fallback text in a text node within the 
> second object than the IE blog entry is incorrect


IN IE 6 the statement seems correct. And after having installed 
IE8beta, it seems you are right in that it is not correct for IE8 
... (Have not tried IE7, and do not trust the IE7 emulation of 
IE8.) However, a better test case than yours is this (since in 
your test, in IE8beta1, the GIF would actually be displayed):

<object data="data:application/x-unknown,ERROR" >
<object type="image/gif" data="object-ie8.gif" >
some fallback</object></object

Either they were wrong, or we misunderstands the issue ... I 
wonder if they mean that if an OBJECT with an working 
data="attribute" URI is found, then then the other nested OBJECTS 
and the rest of the fallback content is ignored.
-- 
leif halvard silli