- From: Victor Engmark <victor.engmark@cern.ch>
- Date: Wed, 10 May 2006 16:25:09 +0200
- To: www-forms@w3.org
Stefano Debenedetti: > > Ulrich Nicolas Lissé ha scritto: > > > > Allan, > > So, to sum up: I don't think accessibility gets lost just by using > > server-side technology. Though AJAX scripting makes it a bit harder to > > build accessible web applications, it's not getting impossible just by > > using that technology. > > In order to detach the discussion a bit from a religious (and > business-model driven) controversy, do you have any evidence backing > your claim? > > I mean something one could compare with careful exams of HTML+script > solutions as opposed to what the WCAG says, such as this one [1]? My 2 cents (sorry for the length): As far as I can see, there are two issues which make one easily accessible and the other one difficult or impossible: Scannability (viewer abilities), and semantics. Scannability boils down to the fact that sighted users very easily detect page changes (as long as they are within the window), and context is obvious from looking at the surrounding text / graphics. For audio or braille browsers it's not obvious how to handle such changes meaningfully: Reading the whole page again would mean a huge overhead for the users (not to mention the problems with quickly changing content), reading just the changed part probably won't provide enough context to make out the meaning of the change, and reading the surrounding text may provide too much or too little information. Visual browsers allow for a graphical view of the data, making proper semantics of content (sections, sub-sections, navigation) essentially unnecessary - Unless the data is very badly structured, sighted users won't have to read all the text to get to the useful information. This has also resulted in table layouts, <blockquote>s for indentation, and other accessibility horrors. Non-visual browsers depend on the semantics of the data to be able to provide a user experience close to that of sighted users. The semantics of (X)HTML is clearly defined - <address> and <li> have specified meanings, which should be respected. JavaScript doesn't have anything like this (AFAIK), and I don't think it's possible to create such a thing; there are infinite semantic possibilities. For example, consider a JS slider which changes the background color - It doesn't have any semantic meaning to a blind user. Then consider the same slider used to provide a seed number to a sentence generator. It definitely has a semantic meaning, but how could you provide that meaning to the browser and user? Also consider that the same result could be implemented in an infinite amount of ways with JS; if you were able to extract useful semantic meaning from any piece of code, you'd be the Einstein of computer science. HTH -- Victor Engmark "a wealth of information creates a poverty of attention" - Herbert Simon
Received on Wednesday, 10 May 2006 14:25:38 UTC