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Re: Guideline 1 in The evaluation techniques document

From: Leonard R. Kasday <kasday@acm.org>
Date: Thu, 24 Jun 1999 17:26:50 -0400
Message-Id: <3.0.32.19990624172648.00f4b8cc@pop3.concentric.net>
To: Nir Dagan <nir@nirdagan.com>, Al Gilman <asgilman@iamdigex.net>
Cc: w3c-wai-er-ig@w3.org
At 04:22 PM 6/24/99 -0400, Nir Dagan wrote:
>Generally null is not white space but the specs say that leading and
>trailing white space in CDATA attribute values can be egnored by user
>agents. E.g., "myval" may be treated as " myval "

In addition, http://www.w3.org/TR/REC-html40/types.html#h-6.2 states that

"Authors should not declare attribute values with leading or trailing white
space. "

Seems to me that rules out " " or am I reading this wrong?  It looks like "
" has both leading and trailing white space in fact.

Len


At 04:22 PM 6/24/99 -0400, Nir Dagan wrote:
>Generally null is not white space but the specs say that leading and
>trailing white space in CDATA attribute values can be egnored by user
>agents. E.g., "myval" may be treated as " myval "
>Regards,
>
>Nir Dagan
>
>http://www.nirdagan.com
>mailto:nir@nirdagan.com
>
>"There is nothing quite so practical as a good theory." 
>-- A. Einstein
>
>On Thu, 24 Jun 1999, Al Gilman wrote:
>
>> 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.
>> 
>> Al
>> 
>> >
>> >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.
>> >
>> >Regards,
>> >Nir Dagan
>> >
>> >http://www.nirdagan.com
>> >mailto:nir@nirdagan.com
>> >tel:+972-2-588-3143
>> >
>> >"There is nothing quite so practical as a good theory."
>> >-- A. Einstein
>> > 
>> 
>
>
>
-------
Leonard R. Kasday, Ph.D.
Universal Design Engineer, Institute on Disabilities/UAP, and
Adjunct Professor, Electrical Engineering
Temple University

Ritter Hall Annex, Room 423, Philadelphia, PA 19122
kasday@acm.org        
(215} 204-2247 (voice)
(800) 750-7428 (TTY)
Received on Thursday, 24 June 1999 17:24:32 GMT

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