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Re: Improving alt (was handling fallback content for still images)

From: Sander Tekelenburg <st@isoc.nl>
Date: Tue, 17 Jul 2007 04:22:19 +0200
Message-Id: <p06240642c2c1cece3796@[192.168.0.102]>
To: public-html@w3.org

At 16:03 -0500 UTC, on 2007-07-15, Robert Burns wrote:

[...]

> Also, as I had suggested earlier, we could use a certain number of
> words rather than characters.

Yes, might be better. Added to the wiki.

Btw, while there, I ran into a counter argument by Gregory Rosmaita:

	While there is a need for brevity in ALT text, it must also be remembered
	that (a) there is no limit on the number of characters in a tooltip

Do we know that for a fact to be the case in every browsing environment?

That aside, tooltips are just one possible mechanism to present alt text. UAs
may yesterday (iCab) today (lynx) or tomorrow (?), present alt text through
different mechanisms. Toooltipd don't even exist in every browsing
environment.

	and (b)
	that requiring user agents to ignore the part of the ALT text that exceeds
	this limit, is a non-starter.

Agreed. Fixed in the updated proposal.

	[...] forcing user agents to discard ALT text longer than 100
	characters would compromise the purpose of ALT text.

I agree force is too much. I'm still convinced authors need to be informed
whwat lengthe they can reliably use though. Judging by my test of current
implementations (see <http://santek.no-ip.org/~st/tests/altlength/>), 'too'
much more than 100 characters compromises the purpose of @alt today. Isn't it
worth to try to improve that situation? Basically, the aim of my proposal is
to make it easier for authors to understand at what point their alt text is
getting too long and they need to use longdesc, while at the same time
improve interoperability (across UAs) by stating how much UAs must *at least*
present to users in a useful way.

After all, it's not useful to be allowed to have a 1000 character alt text if
you can't rely on it being useful to your audience.

[...]

> I also think if the author conformance criteria sets the word limit
> lower than the limit for UA conformance it will help take care of the
> n+1 problem.

I don't know. It has always troubled me that defining UA behaviour (which I
think is a great thing) will mean that some authors will try to be smart and
author to the UA requirements.

Besides, the current text says that authors must limit themselves to x, and
UAs must present *at  least* x. Doesn't that already leave room enough for
'spillover'?

> That is if authors are told to stick to 20 words and UAs
> are told to truncate at 40 words, its only the author's way out of
> bounds that are going to get hit by the limit

*Users* will get hit. The authors may not even realise it.


-- 
Sander Tekelenburg
The Web Repair Initiative: <http://webrepair.org/>
Received on Tuesday, 17 July 2007 02:25:46 UTC

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