[structural navigation] breadth-first walk? in time-to-reach algorith

The ADesigner tool from IBM Japan has a great feature.

This is a shading on the web page that indicates by growing darkness
the amount of time it would take a keyboard user to reach a given
feature in the page.

This puts usability of in-the-page navigation on a basis that
visually-oriented designers can readily appreciate.

In our best practices, we tell authors to put container elements
in their hypertext collecting the contents of semantically-one-thing
regions in the layout.  And give them good accessible names.

The containment structure of a page can be viewed, for example,
using "View / Style / Debug with outline" in Opera.

My question here is:

Does the time-to-reach algorithm take account of the hierarchical
breakdown of the page?  If the author breaks the page down by
semantic regions as we ask, does the time-to-reach score improve?
Does the page lighten up?

If so, what form of hierarchical navigation does the algorithm
assume?

Al

PS:

What form does hierarchical navigation in screen readers take?
In on-screen keyboards?
Is there a consensus core of structural concepts that are
utilized in multiple ATs?

My mental model has been based on something that the user could
achieve with a DAISY book or if the hierarchical structure of the
page has been cast as a WAI-ARIA tree widget (initially collapsed
below the level=2 nodes).

I call this a breadth-first walk of the contents:  regions are walked,
and their accessible names announced that are the children of one
parent node (in the Table of Contents or Accessible Tree structure,
some intermediate nodes in the DOM may be left out).  When the user
finds a major section that they want to drill down into, they start
walking the section names of the children of that node.

Is there anything like that in AT today?

This, to me, is the central target of structural markup in pages.
Walking the accessible names of major blocks to see where you want
to explore the finer structure.

But if this is only available in DAISY, I am ready to back of and
learn what is out there today that we are targeting.

  I was told "header navigation is header navigation and
structural navigation is totally different." At that poing I realized
I don't know what form either takes in screen readers or on-screen
keyboard tools today.

Received on Monday, 24 March 2008 19:07:07 UTC