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Re: Alt content [ was: “Adaptive Image Element Proposal”, now off HTML WG list ]

From: Kornel Lesiński <kornel@geekhood.net>
Date: Tue, 04 Sep 2012 21:13:00 +0100
To: public-respimg@w3.org
Message-ID: <op.wj4nryqate2ec8@aimac.local>
On Thu, 30 Aug 2012 20:10:54 +0100, Mathew Marquis <mat@matmarquis.com>  

> What I’d like to do here is get your thoughts, as authors, on the  
> following:
> 1) Duplicating the `alt` attribute on both `picture` and the fallback  
> `img`
> 2) `alt` specified on fallback `img`, using `aria-labelledby` on  
> `picture` to reference the ID of the fallback `img`

I think there's a third option missing:

3) Don't duplicate the `alt` attribute, reuse fallback in a smart way.

Simply don't use `alt` on <picture> at all. Require UAs to read all  
content of <picture> (including content of <img alt>) when alternative  
text is required.

<picture><img alt="fallback text"></picture>

<picture><img alt="fallback"> text</picture>

<picture>fallback <img alt="text"></picture>

<picture>fallback text</picture>

In all examples above the alt would be identical: read as "fallback text".  
And it would be read basically the same way by <picture>-supporting HTML5  
UAs as HTML4 UAs.

The algorithm for extracting alt this way is quite simple. In jQuery  
notation would be:

$('picture source').remove() // ignore <source>, keep rest of the content

$('picture img').each(function(){
   $(this).replace(document.createTextNode(this.alt)) // Replace <img  
alt="foo"> with "foo"

var alt = $('picture').text() // take all text remaining in  

regards, Kornel
Received on Tuesday, 4 September 2012 20:13:25 GMT

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