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Re: Guideline 1 in The evaluation techniques document

From: Al Gilman <asgilman@iamdigex.net>
Date: Thu, 24 Jun 1999 09:03:23 -0400
Message-Id: <199906241257.IAA172585@relay.interim.iamworld.net>
To: Nir Dagan <nir@nirdagan.com>, w3c-wai-er-ig@w3.org
At 11:56 AM 6/24/99 +0300, Nir Dagan wrote:
>I realy do not understand the idea behind:
>Not allowed - NULL ALT value (ALT="")
>Allowed - ALT value of 1 or more spaces (ALT=" ")
>Both from a semantic/logical point of view and HTML specification 
>these are quite the same thing.

Not quite.  You are ignoring the way logic depends on lexical analysis or
the recognition of word boundaries.  "Lay out" is a verb while "layout" is
a noun.  The logic depends on the lexing.  Whitespace is not guaranteed to
be logically without effect.  Null is not whitespace, space is.  There are
enough situations where this introduces a semantic difference.

In the HTML specification it merely warns that some user agents may ignore
whitespace in certain circumstances.  I do not believe that you will find
this carried forward in either the work on XML normalisation nor in the
Internet-Draft from DRUMS updating RFC 822.  What I am saying is that the
best thinking on this issue is that a null string and linear whitespace are
logically different, a distinction that must be preserved.


>My major reservation with this guideline is that there may be out there 
>many people who took the effort to write accessible pages with alt=""
>where appropriate, and now we tell them to revise their pages, without
>any reason whatsoever.
>Nir Dagan
>"There is nothing quite so practical as a good theory."
>-- A. Einstein
Received on Thursday, 24 June 1999 08:57:44 UTC

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