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Re: UAAG2: Rough Proposal on 2.3

From: Jan Richards <jan.richards@utoronto.ca>
Date: Thu, 13 Dec 2007 14:45:14 -0500
Message-ID: <47618BCA.40707@utoronto.ca>
To: WAI-UA list <w3c-wai-ua@w3.org>

Comments from call added (shall I put it in the Editor's Draft?):

2.3 Provide access to conditional content (P1)

Level A:

1. The user can browse and have rendered any items in a *conditional 
content stack* that are encoded in *technologies* that the user agent 

2. If the dimensions of the items in the *conditional content stack* 
differ, then a configuration should control whether the dimensions of 
the default item or the rendered item are used.

3. If an item in the *conditional content stack* is plain text (e.g. alt
text) then it is available programmatically even when not on-screen.

4. Previously rendered items can continue to be rendered alongside other
items the user requests from the *conditional content stack* unless the 
user agent can *recognize* a mutual exclusion (e.g. conflicting 
@@JR: "Recognize" is in the glossary already

Level AA:

5. The user can set preferences for which items in a *conditional
content stack* are rendered by default.

6. The user is alerted to the presence of non-rendered items in the
*conditional content stack* that are encoded in *technologies* that the
user agent supports.

Level AAA:


"conditional content stack"
The set of *conditional content* items for a given position in content.
The items may be mutually exclusive (e.g., regular contrast graphic vs.
high contrast graphic) or non-exclusive (e.g., caption track that can
play at the same time as a sound track).

"Conditional content"
Conditional content is content that should be made available to users
only under certain conditions (e.g., based on user preferences or
operating environment limitations). Some examples include:

- The alt attribute of the IMG element in HTML 4.
- OBJECT elements in HTML 4.
- The switch element and test attributes in SMIL 1.0.
- The NOSCRIPT and NOFRAMES elements in HTML 4.

Note: Specifications vary in how completely they define how and when to
render conditional content.

Jan Richards, M.Sc.
User Interface Design Specialist
Adaptive Technology Resource Centre (ATRC)
Faculty of Information Studies
University of Toronto

   Email: jan.richards@utoronto.ca
   Web:   http://jan.atrc.utoronto.ca
   Phone: 416-946-7060
   Fax:   416-971-2896
Received on Thursday, 13 December 2007 19:45:24 UTC

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