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Re: DRAFT response Re[3]: Request for PFWG WAI review of Omitting alt Attribute for Critical Content

From: Jason White <jason@jasonjgw.net>
Date: Thu, 29 Nov 2007 21:47:12 +1100
To: wai-xtech@w3.org
Message-ID: <20071129104712.GA2709@jdc.jasonjgw.net>

On Thu, Nov 29, 2007 at 10:48:53AM +0100, Charles McCathieNevile wrote:

> I think we should be clearer.
>
> [[[ If an image is a key part of the content, the alt attribute
> must not be specified with an empty value. ]]]
>
> Is very important. I think we should request that a missing alt value be 
> considered invalid, although for accessibility reasons it is preferred to 
> the more serious error of marking meaningful content which requires an 
> alternative with alt=""

I support Charles' comments.

Furthermore, the most important concept is that there should be only two
syntactically distinct possibilities:

1. Alt with a non-null string, providing an alternative to the image.

2. Alt with a null string, signifying that the image is an artifact of
formatting.

There should not be a third - an omitted alt - which ought, as Charles
suggests, to trigger a syntax error that can be detected by authoring tools
and markup validators.

HTML generating applications (including authoring tools) should not output
alt="" unless reasonable measures have been taken to ensure that the image
belongs to the decorative class. This last point is an authoring tool
requirement which I am sure can be handled in ATAG, if it is not there
already.
Received on Thursday, 29 November 2007 10:47:36 GMT

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