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Re: alt and authoring practices

From: Karl Dubost <karl@w3.org>
Date: Thu, 17 Apr 2008 11:04:38 +0900
Cc: "Bonner, Matt (IPG)" <matt.bonner@hp.com>, "public-html@w3.org" <public-html@w3.org>, "wai-xtech@w3.org" <wai-xtech@w3.org>, "wai-liaison@w3.org" <wai-liaison@w3.org>
Message-Id: <1600B4A7-A35D-41E6-9D1D-171E42E02568@w3.org>
To: Philip Taylor <pjt47@cam.ac.uk>

wow philip. Very very interesting.

Le 17 avr. 2008 à 08:44, Philip Taylor a écrit :
> <img> elements with no alt attribute: 1104466 (47%)
> <img> elements with zero-length alt: 530687 (23%)
> <img> elements with non-empty whitespace-only alt: 11943 (1%)
> <img> elements with non-empty non-whitespace alt: 702702 (30%)

no alt attribute is of a significant proportion. It tells us a bit  
about the Web publish their data. I would be inclined to say that they  
fall in the categories of

* my tools don't give me the possibility to create alt
* I don't know what is a alt, and I have no idea of what is happening  
under the hood.
* I know but I don't care and/or have no time for it.

>> Le 17 avr. 2008 à 06:59, Karl Dubost a écrit :
>>> More challenging, distributions of "text", collect all the text  
>>> contained in alts, sort them out, and then sees what are the text  
>>> which are happening very often (I think about things like "logo"  
>>> emerging, but there might be surprises).
>
> http://philip.html5.org/data/common-alt-values.txt
>
> (It's hard to tell much from that, since a single site with hundreds  
> of pages listed on dmoz.org will significantly distort the results.)

no no. Very informative. Most of the alt text in your sample are  
"functional" texts. Icons for menu, for forms, or visual indicators of  
functional links.

For example, Olivier and I were looking at your results and discussing  
about it. It's interesting to see the "Valid CSS!" decontextualized.  
Apart of Henri's comments on the benefits or harms of badges, a better  
pattern would be more alt="" for the icon valid CSS and a meaningful  
title="" for the link such as "revalidate your document" which is the  
goal of the link.

Something like "Hit Counter" is useless, or "Google" which I guess  
should be "Search on Google".

 From this list another number which would be useful is how many  
alt="text" have a unique text. So something which is unlikely to be  
functional but to be a text for documenting the content of a picture.

>> additional one:
>>    Distribution of text lengths
>
> http://philip.html5.org/data/alt-lengths.svg
>
> (The longest were about 10,000 characters - http://www.coalitionforjustice.net 
>  (looks like actually legitimate alternative text) and http://www.legnotre.com/ 
>  (looks like search engine keyword spam) - but I cut the graph off  
> much earlier, since very few are longer than ~200 characters and it  
> makes the graph more boring.)

Interesting too. Short text in general.

Many many thanks Philip. That is very useful.


-- 
Karl Dubost - W3C
http://www.w3.org/QA/
Be Strict To Be Cool
Received on Thursday, 17 April 2008 02:05:20 UTC

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