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Re: HTML Action Item 54 - ...draft text for HTML 5 spec to require producers/authors to include @alt on img elements.

From: David Poehlman <david.poehlman@handsontechnologeyes.com>
Date: Wed, 14 May 2008 13:27:17 -0400
Message-ID: <F382FDCE518C4858AD8D7D388A8A5FB9@HANDS>
To: "Robert J Burns" <rob@robburns.com>, "Dave Singer" <singer@apple.com>
Cc: <public-html@w3.org>, "W3C WAI-XTECH" <wai-xtech@w3.org>, <wai-liaison@w3.org>, "Dan Connolly" <connolly@w3.org>, "Chris Wilson" <Chris.Wilson@microsoft.com>, "Michael\(tm\) Smith" <mike@w3.org>

sand castles appears twice in this markup and is visible here.  While it 
might be valid syntactically etc, I hope I wouldn't have to hear hundreds of 
itterations such as this.

----- Original Message ----- 
From: "Robert J Burns" <rob@robburns.com>
To: "Dave Singer" <singer@apple.com>
Cc: <public-html@w3.org>; "W3C WAI-XTECH" <wai-xtech@w3.org>; 
<wai-liaison@w3.org>; "Dan Connolly" <connolly@w3.org>; "Chris Wilson" 
<Chris.Wilson@microsoft.com>; "Michael(tm) Smith" <mike@w3.org>
Sent: Tuesday, May 13, 2008 6:43 AM
Subject: Re: HTML Action Item 54 - ...draft text for HTML 5 spec to require 
producers/authors to include @alt on img elements.



Hi Dave,

I hopefully will provide a clear answer to your question and at least
for the two of us end the circle.

On May 12, 2008, at 4:14 PM, Dave Singer wrote:

>
> This entire conversation seems to be be in repeating circles.
> Personally, I would like to see a considered answer to the question
> below, and I don't think I have.  Having, in essence, the question
> or disagreement endlessly repeated is making the mailing list
> tedious to follow.  If we've had a helpful answer, can someone
> repeat it?  If we're on track for getting an answer, can we wait for
> it?  If we don't think an answer is possible, then we need to re-
> frame the question.
>
> "In striving for the best support for accessibility, we would like
> guidance on what to say in a specification on the use of the alt
> attribute for an image when there is no reasonable alt text known.
> It seems as if alt="" would state (probably erroneously) that the
> image is not semantically significant, and alt="an image" -- or
> something similar -- while true, is quite unhelpful.  Some of us are
> uncomfortable with such a string, because it seems to mislead the
> user agent into believing that there is useful alt text, when it may
> be able to do better if it was aware that there is no alt text.  For
> example, it can conclude quite easily by itself that it is "an
> image" and in addition would be able to state its size, and would be
> at liberty to do other analysis (e.g. stating that it had some
> similarity to another image on the page, recognize that it contains
> one or more faces, etc.).  It can also do this in the user's natural
> language, if known.  Because of this, we have considered allowing
> the omission of alt in this case (when no useful alt text is known
> at the authoring point), but we are concerned about this too, as it
> may 'open the barn door' and such a permission to omit may be
> abused. In essence, we have three cases (useful text known, images
> that are semantically insignificant, potentially significant images
> with no known alt text) but only two indicators -- non-empty and
> empty alt text?  Do you have guidance on what to say in a
> specification on the use of the alt attribute for an image when
> there is no reasonable alt text known?"

The alt attribute is only one specialized attribute for non-text
media. For this case it should most likely be alt='' (for legacy
reasons especially). However we have the longdesc attribute aria-
described-by and potentially aria-role or similar attributes to
provide the additional information needed. The alt attribute doesn't
have to do everything.

So an image that is on the page but not part of a link, not presenting
rich text, and not an icon  but still semantically important  would
simply have alt=''. Perhaps something like this for a vacation
photograph discussed on a blog:

<figure><legend>We made a sand castle a the beech</legend><img alt=''
role='meaningful' longdesc='descriptions#sandcastle' ></figure>

Such an approach would:

1) satisfy the requirements you raised
2) provide rich accessibility
3) provide partial machine conformance verification
4) degrade gracefully in existing UAs
5) be easily generated from bulk upload authoring tools

I hope that answers the question satisfactorily.

Take care,
Rob
Received on Wednesday, 14 May 2008 17:27:59 GMT

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