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RE: Updating 2.4, re-revised

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Wed, 30 May 2001 23:12:20 -0500
To: "'Adam Victor Reed'" <areed2@calstatela.edu>, <w3c-wai-gl@w3.org>
Message-ID: <002a01c0e987$e363d000$066fa8c0@750>
I'm not sure there should be an absolute timeout ban.    But I agree there
should be something on timing.

For example,  the case cited had a 15 minute timeout.  I don't know of
anyone who cannot respond in 2 minutes.      A person may need more than 15
min to understand a page,  but that is different than not being able to
respond.  The site could for example,  allow 15 min to pass and then simply
ask "are you there?  Do you need more time?".   It could also reset the 15
min each time the person did something like scroll.    In both cases it
would allow a person to be on line for hours on a single page.  But they
would have to indicate that they were there every so often.   If they left
or shut off their computer etc, the system would time them out after 15 min
of getting no activity or any acknowledgement from them.

That would change 2.4 to


2.4    Do not limit the time that a user has to understand or interact with
your content.  If a timeout is needed, provide the user with a means to
bypass or extend the time.
        * Use automatic refresh and delayed redirection only when
          necessary to bring superceded content up to date.
        * Content must cooperate with user agent mechanisms for
          preventing motion (including flicker, blinking, flashing,
          self-scrolling etc) and for control of the rate at which
          motion occurs.

I WOULD DELETE THE FLICKER COMMENT HERE - AS IT CONFUSES THE SITUATION.
FLICKER IS BARRED ELSEWHERE
 Note that flicker effects can cause
          seizures in people with photoepilepsy.


Gregg


-- ------------------------------
Gregg C Vanderheiden Ph.D.
Professor - Human Factors
Depts of Ind. and Biomed. Engr. - U of Wis.
Director - Trace R & D Center
Gv@trace.wisc.edu, http://trace.wisc.edu/
FAX 608/262-8848
For a list of our listserves send "lists" to listproc@trace.wisc.edu


 -----Original Message-----
From: 	w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org]  On
Behalf Of Adam Victor Reed
Sent:	Wednesday, May 30, 2001 10:36 PM
To:	w3c-wai-gl@w3.org
Subject:	Updating 2.4, re-revised

Time-outs are a real barrier, so leaving them out of the guidelines is
not a solution. If time-outs are needed for economic or security
reasons, the provider ought to provide a bypass - for example, by
letting disabled users register and get a "bypass timeouts" cookie.
So I'll try again:

2.4 Do not limit the time that a user may need to understand or
interact with your content.
        * Provide disabled users with a way to bypass any demand to
          respond within a preset period.
        * Use automatic refresh and delayed redirection only when
          necessary to bring superceded content up to date.
        * Content must cooperate with user agent mechanisms for
          preventing motion (including flicker, blinking, flashing,
          self-scrolling etc) and for control of the rate at which
          motion occurs. Note that flicker effects can cause
          seizures in people with photoepilepsy.

--
				Adam Reed
				areed2@calstatela.edu

Context matters. Seldom does *anything* have only one cause.
Received on Thursday, 31 May 2001 00:13:23 GMT

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