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2.4.5 Proposal

From: Ben Caldwell <caldwell@trace.wisc.edu>
Date: Tue, 07 Mar 2006 14:44:29 -0600
Message-ID: <440DF0AD.8080604@trace.wisc.edu>
To: WCAG-WG <w3c-wai-gl@w3.org>

The following is a proposal meant to address some of the concerns that
have been expressed on the list in recent weeks regarding success
criterion 2.4.5 [1].

<current>
2.4.5  Each programmatic reference to another delivery unit or to
another location in the same delivery unit, is associated with text
describing the destination.
</current>

--------------------------------------------------------------------

Background:

How to meet 2.4.5 [2] contains a fairly extensive editorial note
describing issues related to meeting this SC:

<ednote>
   Editorial Note: The WCAG Working Group is not sure how close the
   "association" between the text and the destination should be. On one
   hand, if you have a page with a list of book titles with links
   saying WORD, PDF, HTML, and TEXT following each title, it seems
   logical that having the title next to the row of links would be
   better than repeating the title in each of the links. It would be
   better for people who look at the page and better for someone
   reading down the page with a screen reader looking for a book title
   and then selecting the type. On the other hand, allowing "text next
   to a link" to suffice for 'associated' would allow one to say "for
   more information" next to a link labeled "click here". This can lead
   to a page of 'click here' links and that is not seen as desirable.
    1. Is there a rule or wording for the success criterion that allows
       one but not the other?
    2. How big is the problem?
    3. Would requiring that all links contain full information about
       their destination (without reading any surrounding text) be
       overly restrictive or not?
    4. Should links be required to make sense when read out of context?
       (Or is this requiring that pieces of content need to make sense
       when removed from the rest of the content?)
    5. Note: Jumping between links or listing the links on a page is a
       common navigation technique.
</ednote>

Here's a (highly condensed) summary of the issues with this criterion as
it is currently written from the list:

- programmatic association of links with text describing the link
destination significantly reduces the number of key presses required to
understand a link

- WCAG 1.0 Checkpoint 13.1 (Clearly identify the target of each link)
was Priority 2

- the phrase "description of the destination" might not be quite right

- some technologies may not provide mechanisms for providing
supplemental information (or hiding it)


--------------------------------------------------------------------

Proposed Revisions:

The following proposal is an attempt to address the above concerns by
splitting the current success criterion into two as follows:

Level 2

<proposed>
2.4.5 Text describing the context of each link can be programmatically
determined or is available from link text in combination with parent
structures.
</proposed>

Level 3

<proposed>
2.4.9 The context of each link can be programmatically determined.
</proposed>

--------------------------------------------------------------------

Rationale:

1.) The proposal replaces "programmatic reference" with the more
understandable term "link"

2.) The proposed replaces "text describing the destination" with, "the
context of each link"

3.) The proposal takes a similar approach to this issue as we've taken
with titles in 2.4.4 and 2.4.7 (required at level 2, descriptive at
level 3) and other SC (timeouts, contrast, etc.). So that, at level 3,
the requirement is more strict than at level 2, requiring that assistive
technologies have access to the link's context without taking focus away
from the link.

4.) For level 2, the idea would be to allow links with the same link
text to different locations at level 2, but only if they are part of a
hierarchical structure that could be be understood by walking up the
tree. Sufficient techniques would then be exactly what we've already got
written up for this technique and failures would occur when ambiguous
links occur without preceding paragraphs, list items, or headers that
describe their context.

5.) The level 3 success criterion would essentially require that either
the link itself be understandable out or context or that a title
attribute (if the tech. supports this type of structure) be present. All
of the sufficient techniques for this SC would also be sufficient to
meet level 2.

Thoughts?

-Ben

[1] SC 2.4.5: links in context
<http://lists.w3.org/Archives/Public/w3c-wai-gl/2006JanMar/0396.html>
[2] How to meet 2.4.5
<http://tinyurl.com/mlvbr>


-- 
Ben Caldwell | <caldwell@trace.wisc.edu>
Trace Research and Development Center <http://trace.wisc.edu>
Received on Tuesday, 7 March 2006 20:44:43 GMT

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