'escape' method

This expands on Jon's agenda item about what we are marking in the content
and the [range of] anticipated assistive processing including UA behaviors
that will be enabled by this markup.

** introductory overview

Here I want to discuss two relaxations on the 'conventional wisdom' 
of accessibility.

a)  problem: from

What it is we need to mark?  Groups of related links.

to

What it is we need to trap and mark up better?  Concentrations of 
under-motivated links.

b) solution: from

Navigation destinations with Table-of-Contents -appropriate hint or 
label or link text.
.. supported by list and go-to methods..

to

Additionally an 'escape' or "get me out of here" method that
- mimics the 'escapable structures' feature in DAISY books
http://www.niso.org/standards/resources/Z39-86-2002.html#Escape
- suffices to replace skip-nav links in the content
- is similar to 'seek' functions in radio tuners and media players.

** discussion

I call it 'escape' because it is available from anywhere within an 
escapable structure, and
not only from the beginning of that structure.  It moves you past 
some current context
that is of a class that the 'escape' method is proper to.  In DAISY 
this is things like
forms and tables.  I think that navbars would be another category 
that this would
be good for.

Skip-nav can be achieved by using the 'escape' method when at the 
start of the masthead.
But we would have to look at what the actual algoritm is so it 
doesn't take a confusing
number of 'escapes' to get to the main content in that way.

This solves a more general problem.

The users who have trouble being lost in navbars will have a problem 
wherever there
is a high concentration of links that are under-motivated and under-structured.
The visual browsing experience allows rapid skimming of the scene, so 
the usability
is not broken by a shotgun blast of many links with loosely 
affiliated context cues
as to what the linked resources might add to the experience.

The eyes-free user and the high-cost-per-input-symbol user both need better
structured ways to manage their review of the action opportunities represented
by the hyperlinks.

Also, while the Table of Contents metaphor is very valuable in 
organizing our work,
navigating indirectly through the Table of Contents is by its 
indirection less likely
to be used.  In the talking book experience, the conventional wisdom is that
we need to serve users who will approach the content as a topic tree and use
the table of navigation, and also users who will play the book like a 
serial tape and
may need some skip or local navigation commands, but generally ignore the
contents tree.

I have been thinking we should try to adapt this bimodal use wisdom 
from the book
domain to the web page domain.

There are of course limitations to the portability of the precedent.  Books are
still, by and large, bigger than web pages.  And they are created in a way that
makes the table of contents more something that reflects the author's mind
than the way web pages get built.  But anyway, giving some way to skip out
of regions of rough sledding is an alternate model of what the 
assistive function
is that I think we should consider.

Of course in the DAISY context we have high-political-correctness people
(the alternate format edition producers) controlling the markup of escapable
sections.  So it makes sense to make the skip command move to the end
of a marked section.  On the web we are not so fortunate.  So skipping to
the first sign of lower link density is practial, if heuristic.

What I am angling for here is that we take a reasonably low level of assumed
commitment from the authors, but still consider an 'escape' method that
would be applicable to a) forms and tables without inspecting further markup,
and b) containers with 'roles' we designate as skippable, including 
'navigation.'

Al

Received on Friday, 15 April 2005 17:50:35 UTC