- From: <jukka.korpela@tieke.fi>
- Date: Thu, 21 Feb 2002 09:53:15 +0200
- To: w3c-wai-ig@w3.org
Michael Fry wrote: > I've been asked to determine if assistive technologies, e.g. > screen readers, can be "directed" by HTML (or something else) > to read specific cells in a layout table in a particular order Your assumption that the answer is "no" sounds correct, since there is no HTML markup or CSS properties for suggesting a reading order, and any heuristic guesses would really be shots in the dark. There might be some work in progress to add features into CSS for this, but what comes closes in _current_ CSS (which is still poorly implemented in browsers) in section "Audio rendering of tables" in CSS2: http://www.w3.org/TR/REC-CSS2/tables.html#q21 and it deals with rendering of tables used for presenting tabular data, not layout tables, and it's interested in the (very important) question of association data cells with headers, to indicate the meanings of data in cells. Even if something related will be added into CSS, it will take quite some to get it implemented. Besides, there would be the problem that we now have with a somewhat analogous construct, the tabindex attribute: authors who use it often _rely_ on it, causing problems to people using programs that don't support the construct at all. And, basically, layout tables are something we should try to get rid of, replacing them with the use of CSS positioning and other CSS features for suggesting layout. Authors who keep using layout tables might consider using tricks like Delorie's trick of using a dummy cell to make the order better when tables are processed rowwise, see http://www.delorie.com/web/ses-hint.html DJ Delorie presents that as a trick to make search engines "see" a document's content in a certain order, but it would work for speech synthesis, too, when performed rowwise by the table structure (and not according to what has been written onto the screen) > On a potentially related note, what do people think about providing > *several* 'skip navigation' links on a page, e.g. one for 'main content,' > one for 'main navigation,' 'local navigation,' etc. It might help, if the page is confusingly complex. I'd say it could be useful partial workaround if you don't want to _solve_ the problem. :-) But if you ask me, I wouldn't intuitively know, for example, what "local navigation" means. Local to what? (The page? The site? Some geographic locality?) > Is there a reason > why are 'skip nav' links seem to be limited to one per page? Not really, I think, but they are commonly presented as a workaround needed to skip over _one_ bulk of irrelevant (for normal use) content. That is, all the different sets of navigational links are regarded as one bunch, to be skipped. If they contain, say, a table of content for the current page, then that set of links is not skippable in the same sense as "navbars" are. A table of content, which is of course not normally an HTML table but a list, is what users normally start with, so I'd make a "skip nav" link point to the start of the table of content. If the user wishes to skip to the beginning of the content proper, e.g. because he has already studied the table of content during his previous visit to the page, he can conveniently use the first item in the table of content. Assuming that the items there are links to the corresponding parts of the text, of course, as they should be. All these "skip over" links are workarounds, not solutions. It is symptomatic that we find it necessary to use _verbs_. Cool links are nouns or noun phrases, not verbs, since they refer to something, instead of telling to do this or that. (Actually, it isn't always necessary to use verbs for "skip over" links; "main content" or something like that might be better.) For constructs like a <pre> block or other things that are potentially very problematic in some modes of use and to some users, "skip over" links are the practical solution at present, unless you can feasibly put the problematic content itself behind a link, on a page of its own. But it is then important to make clear _why_ the user might wish to skip over something and what (if anything) will be missed that way and, hopefully, where a more accessible presentation is available. -- Jukka K. Korpela, erityisasiantuntija / senior adviser TIEKE Tietoyhteiskunnan kehittämiskeskus ry Finnish Information Society Development Centre Salomonkatu 17 A, 10th floor, FIN-00100 HELSINKI, FINLAND Phone: +358 9 4763 0397 Fax: +358 9 4763 0399 http://www.tieke.fi jukka.korpela@tieke.fi
Received on Thursday, 21 February 2002 02:55:30 UTC