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Number of posts in this thread: 9 (In chronological order)
From: Gary Williamson
Date: Apr 16, 2007 5:40AM
Subject: Validation equals Accessibility?
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Generator Microsoft Word 11 (filtered medium) I' m racking my brains to think of reasons why, when I validate my page using W3C validator my page is valid but not necessarily accessible. I can think of a couple but would like some opinions from people who work more directly in this field. Any help would be greatly appreciated.
Also does anyone use any software that checks for accessibility rather than validity?
Regards
Gary
From: Gareth Dart
Date: Apr 16, 2007 5:50AM
Subject: Re: Validation equals Accessibility?
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Valid markup does not equate to accessible markup, unfortunately. They
are both very important but are in many ways separate issues.
There are several options for software that tests the accessibility of a
given page - I'm certain that others will be able to add more but the
ones I use are the firefox extensions 'Web Developer' and the extension
'HTML validator' - both have options for providing feedback on
accessibility as well as validity and are available from the Mozilla
site. I have also recently been trying out the Mozilla Accessibility
Extension, which I believe is authored by a contributor to this list.
There are online tools too: http://www.cynthiasays.com/ Cynthia Says
being one of them.
One caveat I'll add is that running your pages through an automated
testing script of some kind is a helpful step in identifiying any
accessibility issues but is not, by itself, a solution. They won't
always spot everything - only thorough testing by a real human person
will do that.
Cheers,
G
From: Patrick H. Lauke
Date: Apr 16, 2007 8:40AM
Subject: Re: Validation equals Accessibility?
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Quoting Gary Williamson < = EMAIL ADDRESS REMOVED = >:
> Generator Microsoft Word 11 (filtered medium) I' m racking my brains
> to think of reasons why, when I validate my page using W3C
> validator my page is valid but not necessarily accessible. I can
> think of a couple but would like some opinions from people who work
> more directly in this field. Any help would be greatly appreciated.
>
> Also does anyone use any software that checks for accessibility
> rather than validity?
To quote myself, from
http://www.accessifyforum.com/viewtopic.php?p=51724#51724
"think of it this way: you can run a word document through a
spellcheck, and it can tell you that there are no errors...but that
does not mean that your document actually makes any sense whatsoever.
same thing with automated testing tools for accessibility. to make
sure that your site is *actually* accessible, you should really enlist
the help of somebody who knows about accessibility (either on forums
such as this one, or a paid-for service like shaw trust)"
I can make a perfectly valid document that is nothing more than a page
with one huge image, and in that image have all my content etc and an
empty ALT attribute. I can also choose really bad colour combinations
like red text on green background. There...a perfectly valid page, but
hardly accessible.
More subtle examples: a valid page that doesn't use heading elements,
instead using <span class="bigheading"> or some such...
You hopefully see where this is going. Validation only means that
you're following the correct syntax. It doesn't mean that what you're
doing is actually sensible, correct, or accessible.
Conversely, a site can fail validation in certain situations and still
be accessible - sometimes you even have to knowingly break validation
for accessibility's sake (for instance, using EMBED is - if i recall
correctly - still the only reliable way to get flash properly
recognised by some screen readers; using OBJECT, flash satay or some
fancy DOM based method doesn't work correctly in those situations).
P
--
Patrick H. Lauke
From: tedd
Date: Apr 16, 2007 9:20AM
Subject: Re: Validation equals Accessibility?
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At 12:29 PM +0100 4/16/07, Gary Williamson wrote:
>Generator Microsoft Word 11 (filtered medium) I' m racking my brains
>to think of reasons why, when I validate my page using W3C validator
>my page is valid but not necessarily accessible. I can think of a
>couple but would like some opinions from people who work more
>directly in this field. Any help would be greatly appreciated.
>
>Also does anyone use any software that checks for accessibility
>rather than validity?
>
Gary:
There are a lot of terms that appear related like accessible and
validation, but their focus is different.
Validation simply means that your web page meets with the W3C guide
lines, such as:
http://jigsaw.w3.org/css-validator/validator.html#validate-by-uri
Of course the W3C wants to promote accessible web sites, but their
main intent is to get everyone on board with compliance to standards,
hence, no accessibility validation (yet).
Whereas, accessibility has different concerns AND those concerns are
widespread and diverse. No single test will tell you if your web page
is accessible or not. But you can try to solve problems via links
like these:
http://www.etre.com/tools/accessibilitycheck/
http://fae.cita.uiuc.edu/index.php?section=report
http://checker.atrc.utoronto.ca/index.html
http://www.websiteoptimization.com/services/analyze/
http://webxact.watchfire.com/
http://www.accessify.com/
http://www.hermish.com/
http://gmazzocato.altervista.org/colorwheel/wheel.php
And these are just a fraction of the online references you can find
if you look.
Hope this helps -- and thanks for asking, more people should.
Cheers,
tedd
--
-------
http://sperling.com http://ancientstones.com http://earthstones.com
From: Jukka K. Korpela
Date: Apr 16, 2007 12:00PM
Subject: Re: Validation equals Accessibility?
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On Mon, 16 Apr 2007, tedd wrote:
> Validation simply means that your web page meets with the W3C guide
> lines,
Not even that. The W3C has issued several guidelines (including old
accessibility guidelines), and most of them do not affect validity at all.
Validating an HTML document does not even check all the W3C guidelines on
HTML - only the part that has been _formalized_ in a Document Type
Definition. More on this:
http://www.cs.tut.fi/~jkorpela/html/validation.html
> Of course the W3C wants to promote accessible web sites, but their
> main intent is to get everyone on board with compliance to standards,
> hence, no accessibility validation (yet).
I wouldn't say anything like that about W3C aims.
> Whereas, accessibility has different concerns AND those concerns are
> widespread and diverse. No single test will tell you if your web page
> is accessible or not. But you can try to solve problems via links
> like these:
Unfortunately, many accessibility checkers just obfuscate things. There's
actually very little that can be checked automatically in the area of
accessibility. Software purported to do such things may issue silly
warnings that just tell _you_ to check for accessibility.
You need real people to evaluate accessibility. But you can start from
learning about accessibility yourself and using your own judgement then.
Using "different" browsers or common browsers with "different" settings is
a good way to make some quick evaluations. For example, you could install
the Web Developer Extension on Firefox and thereby get nice tools for
switching off stylesheets, JavaScript, images, etc., with simple commands,
to see whether a page degrades gracefully.
--
Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/
From: Joshue O Connor
Date: Apr 16, 2007 12:30PM
Subject: Validation equals Accessibility?
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There is another link in the chain.
The role of user testing is something that is going to gain increasing
visibility in the next few years, (yup, my crystal ball says so).
Involving users in the development process is a natural extension or
even evolution beyond automated accessibility checkers, accessibility
audits etc, it nicely complements and even completes the suite. I a
writing a paper about it at the moment and the thing that has struck me,
is it that user testing is in many situations an elitist exercise - as
very many developers just do not have access to testing facilities,
users of assistive technologies, skilled and experienced usability bods
etc. This is terrible. There should be more affordable quality user
testing facilities IMO they should even be subsidised by government or
by big business as part of their whole corporate responsibility spiel.
Don't know when that will happen, the old crystal ball has let me down
on that one.
Josh
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From: Robinson, Norman B - Washington, DC
Date: Apr 16, 2007 2:30PM
Subject: Re: Validation equals Accessibility?
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Although our policy isn't as up to date as most on this list, I can and
do support manual inspection. It is required. We also recommend this in
our official USPS AS-508-A Section 508 Technical Reference Guide for
Web-Based Information and Applications:
http://www.usps.com/cpim/ftp/hand/as508a/508a_c6_toc.html . Note that
the testing sections are either functional testing or indicate manual
processes.
Again, this is an old approach but the basics are the same and generally
get us to an accessible product. I hope to also address the validation
issue in an update to the web-based information and application chapter.
It is a complex issue to debate, but ultimately I hope to prove that
validation is a keystone for enabling accessibility testing.
Regards,
Norman B. Robinson
Section 508 Coordinator
IT Governance, US Postal Service
phone: 202.268.8246
From: Elizabeth J. Pyatt
Date: Apr 16, 2007 2:40PM
Subject: Re: Validation equals Accessibility?
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I'm glad you figured out that this could be a pitfall.
Most problems with valid code still not being accessible deal with
color contrast (black-on-black is valid code, but poor contrast). You
can also not use your headers well, specify small font sizes, over
use layout tables and mislabel your alt tags (only humans can catch
this error).
Because accessibility testing is about meeting different audience
needs, accessibility testing is actually a multipronged strategy
including
* Color checks
* Text browser/screen reader checks
* Disabling CSS check (low vision users implement their own CSS)
* Checking for captions/transcripts on audio and video.
* Automated Accessibility Report (optional)
http://tlt.its.psu.edu/suggestions/accessibility/verify.html
Actually, I find the automated 508 checers the least useful and find
more problems if I use a browser accessibility plugin like the CITA
tools which disable images so I can see what alt tags are or disable
CSS to see if the page is legible.
http://cita.rehab.uiuc.edu/software/
Speaking of CSS, it is possible to have inaccessile styles. For
instance, you can have a fixed font size set too small or a strange
positioning which makes the flow of your text incomprehensible in a
screen reader. Finally, inline CSS styles (<span style='" tags>)
are often inaccessible because users can't override them (bad for
many low vision users).
I mention this because there's also a mantra that "CSS =
accessibility" out there....
http://tlt.its.psu.edu/suggestions/accessibility/css.html#badcss
Elizabeth
--
=-=-=-=-=-=-=-=-=-=-=-=-Elizabeth J. Pyatt, Ph.D.
Instructional Designer
Education Technology Services, TLT/ITS
Penn State University
= EMAIL ADDRESS REMOVED = , (814) 865-0805 or (814) 865-2030 (Main Office)
210 Rider Building II
227 W. Beaver Avenue
State College, PA 16801-4819
http://www.personal.psu.edu/ejp10/psu
http://tlt.psu.edu
From: Jukka K. Korpela
Date: Apr 17, 2007 4:40AM
Subject: Re: Validation equals Accessibility?
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On Mon, 16 Apr 2007, Elizabeth J. Pyatt wrote:
> Most problems with valid code still not being accessible deal with
> color contrast (black-on-black is valid code, but poor contrast).
Not at all. You have an _extremely_ narrow view on accessibility, if you
think that way. Color contrast is just one of the many features that may
cause problems, and when it causes problems, it's probably poor general
usability (hurting most people) rather than accessibility (hurting "only"
people with special needs).
And it seems that you just formulated your view in a wrong way - but your
view is still limited:
> You
> can also not use your headers well, specify small font sizes, over
> use layout tables and mislabel your alt tags (only humans can catch
> this error).
Surely. And you can write all texts in complicated language so that most
people have great difficulties with it and people with cognitive
disabilities don't understand it at all, or get it all wrong.
There are many ways to break accessibility, and no single tool can cover
all the aspects. Most tools check just a fairly limited number of aspects
in a limited manner. (For example, you can automatically check that
headings are used and that heading levels are not skipped, but that won't
catch many of the really common problems, like using headings with no
information content.)
(Layout tables do not, contrary to popular superstition among
accessibility advocates, create any substantial accessibility problems
when used adequately.)
--
Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/