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Checkpoint 2.2 (timed input): Examples of "required user input"?

From: Ian Jacobs <ij@w3.org>
Date: Sat, 24 Feb 2001 13:36:01 -0500
Message-ID: <3A97FF11.EC0A40CD@w3.org>
To: w3c-wai-ua@w3.org
Hello,

Checkpoint 2.2 of the 26 Jan 2001 Guidelines [1] reads:

  For content that requires user input within a time interval
  controlled by the user agent, allow configuration to make the time
  interval "infinite" (i.e., pause automatically at the beginning of
  each time interval where user input is required, and resume
  automatically after the user has explicitly completed
  input). [Priority 1]

Question: What examples do we have where the user agent
can recognize that content requires user input within a time
interval?

I think I have one example, from section 4.5.2 of the SMIL 1.0
specification [2]. In this example, links only "last" for the time
indicated by the "begin" and "end" attributes:

<video src="http://www.w3.org/CoolStuff">
  <anchor href="http://www.w3.org/AudioVideo" begin="0s" end="5s"/>
  <anchor href="http://www.w3.org/Style"      begin="5s" end="10s"/>
</video>

The combination of active element plus time interval means that user
interaction is limited in time. However, it is not clear to me that 
"user input is required within a time interval" in this case.
Nothing that I can see requires the user to activate that 
particular link.

There may be cases where user input truly is "required" within a given
time interval, but I don't have any examples of those. Perhaps it's
possible for the user agent to open timed user prompts, but I don't
know how that's done by the author (I don't know enough javascript).

I do not think that it's our intention to limit this checkpoint
to cases where user input is "required", only where user
interaction is available. I think that checkpoint 2.2 needs to 
broadened to something like this:

  When active elements are only available for
  a finite time interval controlled by the user agent, 
  allow configuration to make the time interval "infinite" 
  (i.e., pause automatically at the beginning of
  each time interval where user input is required, and resume
  automatically after the user has explicitly completed
  input). [Priority 1]

 -Ian

[1] http://www.w3.org/WAI/UA/WD-UAAG10-20010126/
[2] http://www.w3.org/TR/1998/REC-smil-19980615

-- 
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Saturday, 24 February 2001 13:36:03 GMT

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