- From: Gregory J. Rosmaita <oedipus@hicom.net>
- Date: Sat, 28 Jul 2007 12:55:25 -0400
- To: Lachlan Hunt <lachlan.hunt@lachy.id.au>, public-html@w3.org, wai-xtech@w3.org
aloha, lachlan!
i'm not jason, nor do i pretend to be as sagacious as jason, but
perhaps i can explain the thrust of jason's message (with apologies
to jason, of course)
i'm quite happy to hear that we are in violent agreement on so much,
but i did want to address the question of implicit versus explicit
bindings. the reason youtube works for you is that you can perceive
the entire page, and, thus, can sub-consciously associate disperate
bits of data into a comprehensive whole. for those who -- for whatever
reason -- cannot, however, and explicit binding is necessary, for how
else is the user's assisstive technology to communicate to the user
that item x is related to item y unless there is an explicit
programmatic binding between the two. a screen-reader actually has
some of the same limitations as a blind person -- i can tell you
that i am feeling a plastered wall, but unless someone or something
alerts me to the fact that what i'm feeling is actually a fresco,
i will never know that i have encountered anything other than a
blank plastered wall. what makes screen readers work is the ability
to associate programmatic bindings with objects, so as to communicate
to the user the nature, purpose and function of that object. failing
that, a screen reader is reduced to "screen scraping" to obtain the
contents of a document, akin to a static snapshot, while the page
may dynamically change in response to user action; that change will
not be available to the user, because he or she is working off a
snapshot of the page as it was when first loaded, hence the constant
need to "refresh" the screen reader's snapshot of the document, in
order for it (and by extention, the user) to ascertain what -- or
even whether -- change in content or functionality has occurred.
when i am directed to a youtube page by a friend, the only interaction
i have with the page is that the video plays on-load; i cannot control,
restart, slow down, or find the scattered meta-data on the page, which
means that i can only rely on URIs provided to me by others in order
to listen to youtube content. i believe that google is attempting to
rectify this situation with their beta version of a new interface for
youtube, but the fact remains that without an explicit binding of the
metadata to the object it describes/annotates, a non-visual user has
no means at his or her disposal to mentally perform such bindings by
using the sighted person's gestalt view of the page. for a screen
reader user (or a blind person in general) there is no such thing as
a gestalt view, other than that constructed by their assistive
technology, which cannot communicate a working knowledge of the document
to the user without explicit bindings.
which is why the FIELDSET, LEGEND, LABEL model is so important to
HTML forms as they currently exist. one cannot expect, as stated in the
HTML5 draft that assistive technologies can obtain implicit groupings
by walking the DOM -- there must be some sort of binding between objects
and their descriptors or equivalents... that the FIELDSET, LEGEND, LABEL
model is not more widely used is due mostly to either ignorance on the
part of the author, or a lack of imagination when it comes to applying
style rules to FIELDSETs and LEGENDs. the bindings provided by FIELDSET
LEGEND and LABEL are especially important in forms embedded in a TABLE
for layout purposes -- when i encounter a table-ized form, i first must
inspect the form using TABLE navigation mode, which does not communicate
to me either form controls or their state; in order to use the form,
one must enter into "forms mode", but in order to ascertain that the
correct form field has been chosen, one must leave forms mode, and
return to either TABLE navigation mode or inspect the table-ized form
using a virtual cursor, which is not the most effective way to obtain
meaningful information (the only analogy i can offer is that using a
virtual cursor to inspect a document instance is very much like the
experience of a blind person without a cane or guide dog "air swimming"
the room in an attempt to figure out its dimensions, contents, etc.)
programmatic bindings, therefore, are essential to anyone who cannot
perceive the document instance as a single, integrated entity, which
is a far larger user base than simply those who cannot see.
i hope that this helps to explain why EXPLICIT programmatic bindings
are necesssary; especially as the perception of implicit bindings is
in the eye of the beholder, and, therefore, implicit associations
are extremely untrustworthy, not just from the point of view of a
person's physical capacity to perceive implicit associations, but
for reasons of, yes, internationalization, for one man's convention
is another man's cundundrum.
gregory.
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CARTESIAN, adj. Relating to Descartes, a famous philosopher, author
of the celebrated dictum, Cogito ergo sum--whereby he was pleased to
suppose he demonstrated the reality of human existence. The dictum
might be improved, however, thus: Cogito cogito ergo cogito sum--"I
think that I think, therefore I think that I am;" as close an
approach to certainty as any philosopher has yet made.
-- Ambrose Bierce, _The Devil's Dictionary_
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Gregory J. Rosmaita, oedipus@hicom.net
Camera Obscura: http://www.hicom.net/~oedipus/index.html
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Received on Saturday, 28 July 2007 16:56:41 UTC