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Re: unifying alternate content across embedded content element types

From: Robert Burns <rob@robburns.com>
Date: Tue, 17 Jul 2007 00:21:59 -0500
Message-Id: <E3774338-CD3E-4B9E-BA65-58B58B1927D4@robburns.com>
To: HTML WG <public-html@w3.org>

Hi Sander,

On Jul 16, 2007, at 10:52 PM, Sander Tekelenburg wrote:

> If there indeed is already a textual equivalent in the surrounding  
> prose -if
> that text conveys the author's message- then the image is purely  
> decorative
> and alt="" woud be appropriate.

I have a very different view of what a purely decorative image is. To  
me, a purely decorative image is something like a flourish or a  
dingbat or a colorful border. In many ways these are probably best  
handled through CSS, but if they are included in the semantic  
document, the should be done with alt=''. However, I would never  
consider an image that rightly belongs in the semantic document as  
purely decorative. It may be true that there is sufficient textual  
context provided by the surrounding prose. However, that does not  
make it purely decorative. As a user confronting a page where I  
cannot consume the images (for whatever reason), I would want to know  
what I'm missing.

In other words if I encounter the following:

<p>A long discussion of many different topics.</p>
<img src='00002F2.jpeg' alt="" >
<p>A long discussion of some other topics.</p>
<img src='00022F2.jpeg' alt="" >
<p>A long discussion of many different topics.</p>
<img src='01202F2.jpeg' alt="" >
<p>A long discussion of some other topics.</p>
<img src='0000EF2.jpeg' alt="" >
<p>A long discussion of many different topics.</p>
<img src='00FBBF2.jpeg' alt="" >
<p>A long discussion of some other topics.</p>
<img src='00A73F2.jpeg' alt="" >
<p>A long discussion of many different topics.</p>
<img src='00314F2.jpeg' alt="" >
<p>A long discussion of some other topics.</p>
<img src='09624F2.jpeg' alt="" >

How do I know what those images are. Sure, you can say that I know  
all I need to know because I can trust that the author would have  
provide meaningful @alt or @longdesc if there was anything  else to  
know. I don't think that's the web we have today. alt="" can mean: 1)  
the author used an authoring tool that just throws alt='' on there to  
claim 100% validation; 2) the author put alt='' there to get 100%  
validation and stop the nagging validator; 3) the author place alt=''  
there because they follow the practice you suggest and the meaning is  
sufficiently covered by the surrounding prose; 4) the images are  
purely decorative flourishes and dingbat like flair.

Maybe I'm unusual, but as a user I'd like more clarity about which  
one it is. Earlier had suggested adding some reserved keywords to  
@alt to deal wit this issue. However, I would also add that it would  
make sense for an author to use keywords instead of alt=''to help  
associate the missing content with the surrounding prose. Even  
something like alt='Fluffy', alt='Bill' alt='Sarah' alt='Statue of  
Liberty' would make it clear to the user that if they could consume  
this content right now, this  is its relation to the surrounding  
prose (I'm assuming that these keywords are all discussed in the  
surrounding prose).

For reserved keywords, I think something like alt='_prose' and  
alt='_decorative' would help deal with case 3 and 4.. It would deal  
with case 3 in the way you would like to deal with case 3 in that it  
would not require an author add contextual keywords to the <img>  
element. They would just use '_prose' instead to mean: see prose.  
These keywords would help differentiate the content from the from the  
first two cases of careless authoring (probably a large segment to  
differentiate from).

These keywords would degrade gracefully in that current aural  
browsers, might read them and draw attention to these images  
needlessly. However, it would be a minor update to make them HTML5  
conforming and treat the  images the same as alt=''. Once HTML5  
conformance was reached in an aural UA, the browser could notify the  
user that there was content without equivalents (localized-spoken: "5  
prose images on this page and 3 images unknown" or something to that  
effect).  At the very least it would differentiate images that needed  
accessibility attention from images that did not (right now there's  
no easy way to tell). At least those with disabilities would be  
informed whether they should complain or not to the web-master.

These keywords may be an unnecessary distraction for aural UAs until  
they became HTML5 conforming, but it would help with text-only  
browsers. For those with text-only browsers they would get a better  
idea of what the missing alt values might mean on the missing images.  
It would also assist authoring in that missing keywords would be  
elements that needed further author attention (though still valid  
documents).

I'm curious what you and others think of these ideas. In particular:  
1) the differentiation I'm making between purely decorative images  
and those that are complimentary to the surrounding prose; 2) the use  
of keywords for @alt even when the prose was a sufficient equivalent.  
and 3) the addition of these two keywords: (or something like them)  
_prose and _decorative.

Take care,
Rob
Received on Tuesday, 17 July 2007 05:22:46 GMT

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