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RE: Re-post: Influence of valid code on screen readers

From: Robinson, Norman B - Washington, DC <Norman.B.Robinson@usps.gov>
Date: Wed, 15 Jun 2005 10:03:50 -0400
Message-ID: <98D2018DE18A2D40BC2A04CFB111CB04020D197D@WADCHQSXM16.usa.dce.usps.gov>
To: "Sailesh Panchang" <spanchang02@yahoo.com>, <w3c-wai-gl@w3.org>
Just ensure that you aren't making accessibility tests secondary to
valid code:
I would state generically that even pages that fail validation SHOULD be
evaluated; you should not require valid HTML documents to test for
accessibility. It is not necessary! Section 508 is a legal requirement
where valid HTML isn't always necessary because of the way user agents
(web browser) work through invalid HTML. There is a role for document
type and compliance level (strict) to play in this debate.
That said, section 508 does not explicitly require valid HTML DOCUMENTS,
but I would argue that to meet 1194.22(A through I, L, M, N, & O) are
all performed using VALID HTML CODE. While it may be that not all HTML
is valid in a given web page, you can be certain that if you try and any
of the above accessibility standards are not met, it is because you
tried to do so using invalid code (improper nesting, improper tags,
etc.) or your software is defective. 
Your example of a properly marked up table that the screen reader could
not read as expected, you illustrate how SOFTWARE ( screen readers) are
tools and subject to defects. It could have been the browser, the screen
reader, or any other software interfering. Validation checks eliminate
the problems of manually checking your code when you are trying to
determine what problem occur in accessing information using assistive
technology such as a screen reader. Where does it state you have to make
the entire document valid to provide accessibility? You can choose to
manually inspect all of your HTML that matches the above references if
you prefer. That wouldn't be working smart. I'll be using automated
tools - a validator - that allow me to identify defects faster and then
focus on the issues of 508 compliance based on meaning and context. 
Note that you CAN validate all of the above references to meet the
section 508 accessibility standard using the W3C validator. As an
example, the tags for alt text are pretty well defined. When I validate
my web page with a bad alt tag, it finds the defect and makes it easy to
know what to fix. You can validate parts of a page while not caring if
the rest of the web content may not be valid HTML. Section 508 doesn't
explicitly require you to provide valid HTML, but if your code is not
correct and a user agent and web browser cannot access the information,
then you are not 508 compliant. 
Hope I added to the discussion and didn't waste your time - if I'm a bit
off-topic email me directly and I'll be happy to respond.
Norman B. Robinson

-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Sailesh Panchang
Sent: Tuesday, June 14, 2005 9:44 AM
To: w3c-wai-gl@w3.org
Subject: Re-post: Influence of valid code on screen readers

This raises an important question for tools that evaluate accessibility.

Should only  pages which do not fail validation check be evaluated for
But then few pages  will qualify for automated accessibility evaluation
because Bruce notes:
"... is rare to encounter valid html, and such is not an explicit
requirement. <for Sec 508>"

	I remember a recent instance wherein a complex table  was
apparently marked up "correctly" with headers and id and  yet the screen
reader / self voicing browser   was not able to read it as expected. 
	As it turned out, the id values were not unique in the document
and the page failed the W3C Validator.
	Therefore I feel it is important that accessibility evaluation
should be performed 
	only on documents that are correctly marked up and pass
	Sailesh Panchang
	Senior Accessibility Engineer
	Deque Systems
	Reston VA
	E-mail spanchang02@yahoo.com


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Received on Wednesday, 15 June 2005 14:04:04 UTC

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