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Re: making onmouseover accessible

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 5 Jun 2000 17:36:07 -0400 (EDT)
To: "Leonard R. Kasday" <kasday@ACM.org>
cc: w3c-wai-ig@w3.org
Message-ID: <Pine.LNX.4.20.0006051729530.25127-100000@tux.w3.org>
The story (as far as I understand it, and I have been following it for a
couple of years now) goes like this:

javascript effects do not reliably work in all browsers. So it is important
not to rely on Javascript for function. There are two parts to this. One is
to do as Len suggested, and provide a server-side equivalent (for example
form validation can be done on both sides). The other (especially where there
is no real functionality added to the page, for example in a mouseover
highlight, is to add a focus event - most good browsers will allow the user
to focus an element via the keyboard, and functionally a mouseover is
equivalent as a user behaviour, although for historical reasons the language
support for this is fairly poor (HTML provides fair to appalling support for
this aspect of accessibility and browser implementations tend to fall a
little short of that. Sigh. I am pleased to note that there are great
improvements in the model being used by the Scalable Vector Graphics
language, although I am waiting to see the implementations at work).

Charles McCN

On Mon, 5 Jun 2000, Leonard R. Kasday wrote:

  There was a thread back around the beginning of april about text menus that 
  popped up when the mouse passed over them (the celebrated "mouseover" 
  action), and how to make them accessible.  The discussion seemed to end at
    http://lists.w3.org/Archives/Public/w3c-wai-ig/2000AprJun/0015.html 
  without an answer.
  
  There's a simple way to make a functional equivalent of mouseover on a 
  object if there isn't something already defined for clicking on that 
  object.  Just make that object a link so when you click on it it brings up 
  a new page with content equivalent to what pops up with the mouseover.
  
  What if the button already does something, say it's a link and the 
  mouseover brings up summary info that helps you decide if you want to click 
  that link?  In that case you could have an additional link you'd click to 
  bring up the info.  Similar to a D link.  Perhaps an "M" link?   You could 
  make the "M" links visible or not under control of a style sheet.  Also, 
  the page brought up by the M link would have a link to what clicking on the 
  original object would have produced.
  
  Instead of an M link you could have a transparent image to which you could 
  add appropriate alt text. Hmm... - except a transparent image wouldn't be 
  suitable for sighted people with motor disabilities.
  
  Of course, you also have to be sure the average user knows about this stuff.
  
  There's also the long description but that may be used for other stuff and 
  isn't yet implemented on all browsers.
  
  Len
  --
  Leonard R. Kasday, Ph.D.
  Institute on Disabilities/UAP, and
  Department of Electrical Engineering
  Temple University 423 Ritter Annex, Philadelphia, PA 19122
  
  kasday@acm.org
  http://astro.temple.edu/~kasday
  
  (215) 204-2247 (voice)  (800) 750-7428 (TTY)
  
  The WAVE web page accessibility evaluation assistant: 
  http://www.temple.edu/inst_disabilities/piat/wave/
  

--
Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053
Postal: GPO Box 2476V, Melbourne 3001,  Australia 
Received on Monday, 5 June 2000 17:36:13 GMT

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