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Re: questions for SC2.3.1 , 2.4.9, 2.4.4

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Mon, 2 Feb 2009 23:03:33 -0600
Cc: public-comments-wcag20@w3.org
Message-Id: <B4205C47-6AE4-4157-BCBB-EF2EC2A14F19@trace.wisc.edu>
To: Kapsi Maria <dpsd01022@aegean.gr>


Hi Kapsi

see response below in line

Gregg
-----------------------
Gregg Vanderheiden Ph.D.
Director Trace R&D Center
Professor Ind and Biomed Engr
University of Wisconsin-Madison







On Jan 30, 2009, at 4:18 PM, Kapsi Maria wrote:

> Dear Group,
>
> I am currently working on my thesis and investigating the  
> application of WCAG2.0. I would like to ask two questions:
>
> 1. SC2.3.1 mentions “Web pages do not contain anything that flashes  
> more than three times …” I was wondering if / how such periods are  
> affected in case for more than one flashing items on a single page.  
> Does the positioning of these items matters (e.g. if these are side  
> by side or on top anf bottom)?

This is covered by full description of "General and Red Flash  
Thresholds.  Just click on the term in the success criterion and it  
will take you to the definitions.   The full details are there - but  
in short the answer to your question is that the threshold is a  
function of all of the activity on the page.  The positions does not  
matter for this success criterion but the percent of the screen that  
is flashing and the simultaneity of the flashing do.   There is a free  
tool you can download that will evaluate pages for you.    Go to http://trace.wisc.edu/peat


>
> 2. Could you please make clearer to me the difference between SC.  
> 2.4.9 and SC.2.4.4?

the difference is the phrase   "or from the link text together with  
its programmatically determined link context"
which you will find in 2.4.4. but not in 2.4.9.
Basically 2.4.4. allows the context to be in the link  OR in the text  
that can be programmatically determined from the link --  while  2.4.9  
at level AAA is stricter and requires that the context be in the link  
itself.


  This may be easier to understand if you look at the techniques that  
are sufficient for 2.4.4 (which permits the user of context) but not  
for 2.4.9:
H33: Supplementing link text with the title attribute
H77: Identifying the purpose of a link using link text combined with  
its enclosing list item

H78: Identifying the purpose of a link using link text combined with  
its enclosing paragraph

H79: Identifying the purpose of a link using link text combined with  
its enclosing table cell and associated table headings

H80: Identifying the purpose of a link using link text combined with  
the preceding heading element

H81: Identifying the purpose of a link in a nested list using link  
text combined with the parent list item under which the list is nested


> Thank you in advance,
> Maria
Received on Tuesday, 3 February 2009 05:04:21 UTC

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