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Re: Proposal for Changes to Keyboard Navigation

From: Tantek Çelik <tantek@cs.stanford.edu>
Date: Wed, 12 May 2004 04:23:24 -0700
To: Doug Schepers <doug@schepers.cc>
Cc: <www-style@w3.org>
Message-ID: <BCC752CC.3D7E8%tantek@cs.stanford.edu>

On 4/14/04 11:53 AM, "Doug Schepers" <doug@schepers.cc> wrote:

> Hi, folks-
> I realize that this comes too late, since Last Call for CSS3 was quite some
> time ago

Yes, unfortunately these comments came much too late to affect the
functionality in the spec.

> but there are a couple of considerations for keyboard navigation
> that would enhance their use in SVG(+XBL) applications. I have made a page
> which addresses these issues, discusses them in detail, and provides use
> cases and demos. [0]
> The first is relatively minor: for directional navigation [1], in addition
> to URIs, nav-index values of elements in the current document should be
> valid values for nav-up, nav-down, nav-left, and nav-right.

This does not work since multiple elements may have the same nav-index,
whereas the uniqueness of ID values makes that work in a predictable

> My rationale is
> that this is more consistent with the nav-index system, is less verbose,
> does not require that the focus target have an "id" attribute, and would be
> easier to assign and track programmatically. I recognize that this is not
> necessarily the initial intent on directional navigation --that directional
> navigation was partly intended for inter-document navigation-- but this use
> case is particularly pertinent in SVG, at least (and probably in other host
> languages like HTML, sometimes). This aspect of it, admittedly, is a bit
> muddled... when does a directional nav key move to another document, and
> when does it stay in the same document?
> The second is that currently, there is currently no provision for
> hierarchical navigation [2] within a document.

No that is not true.  There is an optional target frame value which can be
used for directional navigation across frames or embedded objects,
essentially from one document to another.  The ability to load another
document via directional navigation has been dropped from this version.

> I propose that nav-index
> allows, as an optional value, a parameterized list of integers rather than a
> single integer. Each parameter would act as a local index for that
> heirarchical "level," and would require a special key sequence for
> navigation up or down levels. This is just one possible solution, of course,
> but it outlines the problem domain. In addition, a special cue (visual,
> and/or aural, and/or whatever) should be given when hierarchical options
> exists. This is certainly more radical than the first suggestion, but an
> elegant model that considers both of these aspects might be designed.
> I have also brought up these issues on the www-svg list, but decided to
> repeat them here for possible future inclusion into the CSS Spec.
> Regards-
> -Doug
> [0] http://www.schepers.cc/walkingtalkingsvg.html#DirectionalNavigation
> [1] http://www.schepers.cc/walkingtalkingsvg.html#DirectionalNavigation
> [2] http://www.schepers.cc/walkingtalkingsvg.html#HierarchicalNavigation

This unnecessarily complicates both the implementation of directional
navigation and the user interface, and therefore doesn't make sense to add.


Tantek Çelik
editor, CSS3 Basic UI module
Received on Wednesday, 12 May 2004 07:29:01 UTC

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