[html4all] Object element support

[Robert J Burns]

HI Leif,

On Aug 22, 2008, at 9:16 PM, Leif Halvard Silli wrote:

> Robert J Burns 2008-08-22 13.05:
>
>> On Aug 22, 2008, at 6:36 AM, 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>
>>>
>>>
>>>>> So you don't hink a validator should OK this?
>>>>
>>>> No, I think the validator should throw an error for the IMG  
>>>> element.
>
>    [...]
>
>>> So, if I want to offer some flash to those that enjoy flash, but a
>>> nice mark-up with some images as fallback for the other readers,
>>> then this would not be good enough, you say. Because then the
>>> screen readers would get some IMG elements.
>
>    [...]
>
>> That is a use case I had not considered (multi media like flash
>> falling back to multi media HTML). I agree it should be permitted.
>> However, then I'm left wondering what you meant by your original
>> OBJECT element objections. It seems your example should be both
>> document conforming and is also handled properly even in HTML4.01.
>
>
> Well, in a way it is linked to this use case. The question is: Is
> there a need for the distinction short vs. long fallback? As
> sighted, grasping an image is fast. Describing it in words might
> take longer time to read etc.

Again, I want to discourage this distinction between short and long (I  
know I sound like a broken record if anyone remembers those). When  
we're talking about OBJECT and other elements that can contain markup  
as alt text, the distinction of short and long is not so important  
(with the alt attribute it is important since there's really no way to  
even separate thoughts into separate paragraphs so it needs to be  
fairly short). There is however an important difference served by the  
alt attribute (or the contents of an element) and longdesc (or another  
such attribute) even if it is not the length of the equivalent text.  
That important difference is that one mechanism is for alt text — text  
that is to be replaced and serve as a seamless replacement for the  
embedded media — and the other mechanism is for descriptive text  
equivalents — text that is a subject or visual description of the  
embedded media not necessarily suitable to replacing the media in the  
present document.

Once both the alt text and the descriptive text equivalent (like that  
referenced by the longdesc attribute) can contain markup, then there  
is no need to arbitrarily limit the length of the content (whatever  
length the author requires is appropriate). UAs can provide users with  
navigation capabilities to skip paragraphs or move to the next heading  
element, etc. However, the need for separate mechanisms for alt text  
and descriptive text still remains.

> For the IMG, the @longdesc is place you can jump /to/. However,
> perhaps what is really needed is to be able to jump /over/? I.e.
> if - as Jason said - the fallback is always long. Consider this:
>
> <p><object data="src" title="Complex Diagram">
> <table summary="The ins and outs of this and that.">
> <caption>Complex Diagram
> <a href="#next-paragraph">Skip to next paragraph.</a>
> </caption><tr><th [... etc ...]</table></object></p>
> <p id="next">....</p>
>
> So, perhaps, what I said about being able to jump to a long
> description, could be replaced with an advice to authors that they
> provide a way to "Skip over" the (long) fallback? Just as it is
> recommended to be able to skip over navigation and to main
> content? Or, perhaps simply adding a table summary would be
> enough? ;-)
>
> (Seems like my view on this has developed.)

To me adding the longdesc attribute (or a new textdesc attribute) to  
all embedded media elements serves the needs of providing a  
descriptive text equivalent (as opposed to an alt text equivalent).  
The markup itself then provides a means for users to skip over, skim  
and otherwise navigate the content.

Take care,
Rob