- From: Ian Hickson <ian@hixie.ch>
- Date: Tue, 14 Aug 2007 07:42:05 +0000 (UTC)
- To: Jason White <jason@jasonjgw.net>
- Cc: HTMLWG <public-html@w3.org>
On Tue, 14 Aug 2007, Jason White wrote: > > The assumption that most authors won't add markup to assist non-visual user > agents and assistive technologies is also not a good starting point from which > to discuss accessibility. (The following isn't intended to make any judgements on the various proposals for how to handle associating header cells with data cells in tables. I'm just discussing language design at an abstract level here.) There are two concerns with regard to specialised markup such as markup intended for non-visual user agents. The first is that most authors won't necessarily use the markup at all. That's not a huge problem, though of course it is a disadvantage of such solutions and should be taken into account (in particular, all other things being equal, if two solutions differ only in that one will get used by authors even when they don't think of users with unusual setups but the other won't, then the former is likely better). The second is that authors will misuse the markup. This is a much, much larger, and very real, problem. If markup is misused more than it is used correctly, especially if the misuse is indistinguishable from correct use from a computer's point of view, then the feature can in fact end up making the user experience _worse_ for users in ususual configurations than the absense of any feature at all. An example of this would be the usemap="" attribute on <input> elements. I recently decided to not supports this attribute on <input> elements in HTML5, after having done a thorough study which discovered that in almost all cases, pages that used the usemap="" attribute on <input> elements actually behaved better in user agents that did not support that attribute than in user agents that _did_ support it. [1] It's sadly the case that most features that don't have an effect in the most common configuration (the configuration most often tested by authors) end up abused like this, which is a very strong reason to avoid this kind of feature when designing the language. Having said that, it's not always bad. The alt="" attribute, for instance, is used widely, and is used correctly in a significant fraction of cases. That's why we have to examine each case individually, and is why research into how features are actually used is so important. -- Footnotes -- [1] This was a thread in which I was dealing with feedback sent to the WHATWG list some time ago. The e-mail in which I detail the study is here: http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2007-August/012334.html -- Ian Hickson U+1047E )\._.,--....,'``. fL http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 14 August 2007 07:49:22 UTC