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

From: Charles McCathieNevile <chaals@opera.com>
Date: Sun, 15 Jul 2007 16:45:54 +0900
To: "Sander Tekelenburg" <st@isoc.nl>, public-html@w3.org
Message-ID: <op.tvhw6squwxe0ny@widsith.local>

On Sun, 15 Jul 2007 06:29:13 +0900, Sander Tekelenburg <st@isoc.nl> wrote:

> What about this then:
>
> - Authors must use no more than n characters as the value of the alt
> attribute. For longer alternatives authors must use longdesc.

I don't think this makes sense, because as already noted there isn't some  
magic number of characters that is useful. Take into account the fact that  
some languages require far more characters for the same power of  
expression and you are walking into the trap of choosing bad alternatives.

> - UAs must make at least the first n characters, of the alt attribute  
> easily discoverable and available to users when the image is, for
> whatever reason, not presented.

Tooltips, or some similar overlay, are likely to be the only effective  
way. Too many pages are, unfortunately, designed so that changing the  
dimensions of the space taken by an image will make them unreadable.

But there are fundamentally different use cases for alt and longdesc. The  
first one is necessary instead of the image - and if it isn't, it was  
excessive work for the author. The second is for those cases where a full  
description is necessary, but should not be inflicted on people all the  
time. (working with a screenreader for a bit will make it clear why this  
ability to ignore it is desirable).

An equivalent should generally be succinct (a picture is worth a thousand  
words, but they are used to save inflicting a thousand words on the user).  
A description should generally be complete.

The fact that title is typically displayed with a tooltip is not that  
relevant - and it is easy enough to distinguish them in implementations if  
that is desirable.

> (For example, UAs may present the alt text in place of the
> image; or through a tooltip or in a status bar on hovering the indicator  
> of the missing image; etc.)

cheers

Chaals

-- 
   Charles McCathieNevile, Opera Software: Standards Group
   hablo español  -  je parle français  -  jeg lærer norsk
chaals@opera.com    Catch up: Speed Dial   http://opera.com
Received on Sunday, 15 July 2007 07:46:23 UTC

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