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

Is this something we should be chiming in on?

--> Mike Squillace
IBM Human Ability and Accessibility Center
Austin, TX

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----- Forwarded by Michael A Squillace/Austin/IBM on 11/29/2007 08:35 AM 
-----

"David Poehlman" <poehlman1@comcast.net> 
Sent by: wai-xtech-request@w3.org
11/29/2007 06:08 AM

To
"Jason White" <jason@jasonjgw.net>, <wai-xtech@w3.org>
cc

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







I guess this is not an argument for rejecting validity of alt+="", but in 
order to be bypassed, it will be severely abused as is the summary for 
tbles.

----- Original Message ----- 
From: "Jason White" <jason@jasonjgw.net>
To: <wai-xtech@w3.org>
Sent: Thursday, November 29, 2007 5:47 AM
Subject: Re: DRAFT response Re[3]: Request for PFWG WAI review of Omitting 

alt Attribute for Critical Content



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.