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issues from WCAG 2 intro session

From: Christophe Strobbe <christophe.strobbe@esat.kuleuven.be>
Date: Wed, 15 Oct 2008 11:56:54 +0200
Message-Id: <6.2.5.6.2.20081015103425.02528cb0@esat.kuleuven.be>
To: WCAG <w3c-wai-gl@w3.org>

Hi,

Two days ago, I taught a WCAG 2 introductory session to a small group 
of people who audit websites for accessibility.
Here are a few questions and concerns that were discovered either 
during my preparation or the discussion we had.

1. Statement of partial conformance:
<http://www.w3.org/TR/2008/CR-WCAG20-20080430/#conformance-partial>
(A) This section says that 'The form of that statement would be, 
"This page would conform to WCAG 2.0 at level X if the following 
parts from uncontrolled sources were removed." ...'
I assume that this would need to be followed by the other required 
parts of a conformance claim 
<http://www.w3.org/TR/2008/CR-WCAG20-20080430/#conformance-required>, 
but this is not stated.

(B) This section also requires that the excluded content 'is 
described in a way that that users can identify (e.g. they can't be 
described as "all parts that we do not control" unless they are 
clearly marked as such.)'
However, it is not clear where this description should be included: 
is it sufficient to only describe the excluded content in the 
conformance claim or should the excluded content also be identified 
in the conforming part of the content. For example, if you pull in 
image ads without alt text, what would you need to do?
Which of the following would be sufficient?
(b1) Conformance claim says that ads from ad server XYZ are excluded. 
Nothing special is done in the content. (Readers don't read 
conformance claims.)
(b2) Conformance claim says that ads from ad server XYZ are excluded. 
In the web page, the text "advertisement" is added above or before 
every ad. (Readers don't read conformance claims.)
(b3) Conformance claim says that ads from ad server XYZ are excluded. 
In the web page, the text "ads by XYZ" is added above or before every 
ad. (Readers don't read conformance claims.)
(b4) Conformance claim says that ads from ad server XYZ are excluded. 
In the web page, the text "ads by XYZ" and a warning (or a link to 
the relevant section in the conformance claim) is added above or 
before every ad.


2. More info on how partial conformance and conformance requirement 5 
interact would be welcomed.
For example, if you have a page that triggers a semi-transparent 
Flash overlay (as an alternative to a pop-up prompt or a new window - 
e.g. for authentication) that traps the keyboard, and you exclude the 
Flash through a statement of partial conformance, does conformance 
requirement 5 still apply? In my opinion, the intent is that the 
conformance requirements still apply, but that is not clear from the 
section on partial conformance.
According to our definition of "relied upon" the content still needs 
to conform if Flash is turned off or not supported, but I'm not sure 
if readers understand the implications of that definition.


3. The audience also asked if links to other media (PDF, audio, 
video) need to warn users in (or near) the link text (SC 2.4.4 Link 
Purpose (In Context) - Level A). Such a link would cause a change of 
context (3.2.2 On Input - Level A; 3.2.5 Change on Request - Level 
AAA), but who would include link activation in "Changing the setting 
of any user interface component" (SC 3.2.2) - even though the 
definition of user interface components includes links.


4. SC 1.4.2 Audio control 
<http://www.w3.org/TR/2008/CR-WCAG20-20080430/#visual-audio-contrast-dis-audio>: 
If there is a mechanism to pause or stop the audio or to control its 
volume, it is allowed to play automatically and for more than 3 
seconds. This means that a screen reader user needs to find that 
mechanism while the audio is still playing, i.e. interfering with the 
speech output of his/her screen reader. So even content that passes 
this SC can interfere with the user's ability to use the whole page.


5. When I created a list of success criteria that apply to 
synchronised media, I found the following:
SC 1.2.2 at Level A requires captions. If authors want to conform at 
Level AA, they also need to pass SC 1.4.4 (Resize text). If captions 
are implemented as text (closed captions), SC 1.4.4 applies to the 
captions, since there is nothing in the SC that says that captions 
are exempted. If video plugins don't have a resize functionality, 
this needs to be implemented in the content. Are there any plugins 
for video that can resize captions? If not, in which formats can 
authors implement functionality to resize text? (SMIL??)

Best regards,

Christophe



-- 
Christophe Strobbe
K.U.Leuven - Dept. of Electrical Engineering - SCD
Research Group on Document Architectures
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BELGIUM
tel: +32 16 32 85 51
http://www.docarch.be/
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Received on Wednesday, 15 October 2008 09:57:39 GMT

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