- From: <schwer@us.ibm.com>
- Date: Tue, 15 Feb 2000 10:05:16 -0600
- To: Charles McCathieNevile <charles@w3.org>
- cc: User Agent Guidelines Emailing List <w3c-wai-ua@w3.org>, WAI PF group <w3c-wai-pf@w3.org>
Charles, One of the things I brought up at the WAI-PF FTF was a need to determine the list of accessible actions mapped for a given element. That said, we should not need to fire a specific event to activate them. We simply need to activate them. For example, if a mouseover drops a menu item from JavaScript there should be an action in the list of actions you mention that describes the action and a method that enables you to activate it. This would also help with AccessKeys. AccessKeys could key off the method to give an item focus by default, the first activation mechanism possibly and then the rest of a set of method(s) that would allow you to selectively activate the function you want. The combination makes AccessKeys much more powerful. Today, in DOM 2, we have an DOMOnActivate event which would be fired on activation. I would much rather find out what function was activated as opposed to the device specific activation notification like onclick. Does this make sense? So, what we could have are these which is in line with alot of what you are saying: DOMOnFocusIn ( in DOM 2 - Merger of onMouseOver, onFocus) DOMOnFocusOut (in DOM 2 - Merger of onMouseOut, onBlur) DOMOnActivate (in DOM 2 - with a parameter indicating which method was triggered or is to be triggered) We may desire pre and post notification. DOMOnPointerMove (new - replaces onMouseMove) DOMSelectionChange (new - for SelectionModel) Regarding the above, would there be any reason to add event filter capability? Another consideration we should discuss is should we have a "default" activation method. Also, should a DOM element have a method to indicate if actions are mapped to the element? Good stuff Charles. Thanks for bringing this up again. Rich Rich Schwerdtfeger Lead Architect, IBM Special Needs Systems EMail/web: schwer@us.ibm.com http://www.austin.ibm.com/sns/rich.htm "Two roads diverged in a wood, and I - I took the one less traveled by, and that has made all the difference.", Frost Charles McCathieNevile <charles@w3.org> on 02/15/2000 01:41:33 AM To: Richard Schwerdtfeger/Austin/IBM@IBMUS cc: User Agent Guidelines Emailing List <w3c-wai-ua@w3.org>, WAI PF group <w3c-wai-pf@w3.org> Subject: DOM events Re: PROPOSAL: User Agent Issue 190: Cross posted to Protocols & Formats and User Agent groups I think we should take a step back and look carefully at this again. Implementing an event model is important if we accept that the web that is moving into the future is going to rely on scripting and dynamic effects. Although there will be a requirement for some time to come that it be possible to use the web without these things, I believe that by ignoring them altogether we are hiding our heads in the sand - we must work out how to make them accessible. The basic requirement is to make the interactions that the user can have, as defined by the content itself, available to the user without requirement for a specific type of hardware interface. For example, relying on the presence of a mouse, or of a visual display of a certain size, is unreasonable. In HTML terms, what is required is that the User Agent provide some mechanism to programmatically trigger the event trigger attributes, and that that function is also available in a device-independent manner to the greatest extent possible. One approach to this is to look at the new DOM event set, and map the current HTML towards that set. (For a note on why this is a good idea, read the original HTML 4.0 specification at the relevant point...) Here is a possible way to handle the events: onClick, onDblClick, onKeyPress, onKeyDown, onKeyUp can all be mapped to the new onActivate, using a parameter where appropriate. I would suggest that the value of the parameter be numeric, and that we require of the DOM group that this event be able to take sufficient parameters to encompass a multiple click, or differentiating between some number of different keys (I would suggest that 10 is a better number than 2, for example) onMouseOver, onFocus be merged to the new equivalent, and similarly with onMouseOut and OnBlur. onMouseMove is a bit tricky. Where mouse things are used with X,Y parameters there is some careful thinking needed to work in a non-visual space - in some cases a more object-oriented approach will solve the problem (this is a Web Content Question), but there are cases where it is just very difficult - the same problem that arises in trying to deal with raster-based graphics. I think the rest of the events can stay as they are. Gregory has already pointed to the potential problems raised by ill-considered use of mutation events such as onChange for submitting forms, and in any event that does not rely on a particular type of user interface. To a certain extent this is going over old ground. Which I find extremely frustrating, but think is pretty important and we still need to get it right. Charles McCN On Mon, 14 Feb 2000 schwer@us.ibm.com wrote: This is why we were pushing the DOM2 event model as P2. It is unrealistic to expect the DOM WG to scrap their entire event model for accessibility. We should be able to improve upon it in terms of device independence. Having people start developing to the DOM 2 event model will not require them to rewrite the whole thing. I do appreciate your concerns. Rich
Received on Tuesday, 15 February 2000 12:09:11 UTC