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Re: OnChange in dropdown combo box used for navigation

From: Vadim Plessky <lucy-ples@mtu-net.ru>
Date: Wed, 19 Dec 2001 09:58:49 +0000
Message-Id: <200112190714.fBJ7EhH24092@post.cnt.ru>
To: "STELZER,MELINDA" <melinda_stelzer@non.hp.com>, w3c-wai-ig@w3.org
Helo Melinda!

On Tuesday 18 December 2001 21:42, STELZER,MELINDA (Non-HP-PaloAlto,ex1) 
|   I was reading the discussion below concerning two different ways of
| handling pages that use a dropdown, or "combo box" control as a navigation
| tool.  In one method, the user must press the form button to cause the
| browser to go to the new destination, and in the other method, the
| "OnChange" javascript event causes the choice to take effect as soon as the
| selection is made.
|   I am trying to assess whether using the OnChange event to activate
| dropdown navigation controls is accessible or not.  According to Charles,
| Jaws users often have problems with it.

There is a requirement in Accessibility Guidelines that site should be 
accessible with JavaScript turned Off.
If you turn off JavaScript,   "combo box" control will never receive OnChange 
event. So, user browsing your web site will never reach location if you use 
OnChange even to make selection and navigate further.

|   There is a work around: pressing "ALT-DownArrow" will produce the effect
| of pressing the mouse button and holding it, and allow the user to
| subsequently browse the dropdown with the arrow keys, without activating
| the OnChange event.  Freedom Scientific says their users generally know
| this technique. Is it true?

No, it's not know technique (at least to me)
I have to admit that I do not have accessibility problems and always use 
mouse. I use keyboard only for entering text. 
|   Do other assistive tools have problems with the OnChange method of
|   activating dropdown navigation?

Can you explain what do you mean here, please?
What do you refer to as "assistive tools"? 

|   -----Original Message-----
|   From: Charles McCathieNevile [mailto:charles@w3.org]
|   Sent: Sunday, December 09, 2001 7:19 AM
|   To: David Woolley
|   Cc: w3c-wai-ig@w3.org; cturne@essex.ac.uk
|   Subject: Re: Fw: [webwatch] Fw: [htmldesigners] What's the difference
|   visually?...
|     This sounds like a case of Document Object Model (popularly called
|     JavaScript) onchange events being used.  The change wouldn't be
|     recognized until the mouse button was released.  It's not an HTML
|     problem, but a designer problem (designing only for clicking with a
|     mouse).

Indeed, OnChange event is related to DOM.
You may want to read DOM specification to see how it works.
Modern (and valid) technique is to use EventListener (addEventListener DOM 
method). Than you will have more flexibility *what to do and where*

|     Plain HTML will not do this.


Vadim Plessky
http://kde2.newmail.ru  (English)
33 Window Decorations and 6 Widget Styles for KDE
KDE mini-Themes
Received on Wednesday, 19 December 2001 02:15:23 UTC

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