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Re: Events (Xposted)

From: Paul Adelson <paul.adelson@citicorp.com>
Date: Thu, 29 Oct 1998 10:58:57 -0600
Message-Id: <199810291659.LAA23140@egate2.citicorp.com>
To: Charles McCathieNevile <charlesn@srl.rmit.edu.au>, "w3c-wai-gl@w3.org" <w3c-wai-gl@w3.org>
Cc: WAI UA group <w3c-wai-ua@w3.org>
Sorry for the cross-post, but there is an important issue being overlooked
here that pertains to both UA and PAGL:

onMouseOver can enhance accessibility and there is no effective alternative at
this time, yet people are suggesting it not be used.

For low-vision users, it is very helpful to get extra visual feedback -- as
can be provided by highlighting a link when the mouse cursor passes over it.
Using the events in this way can improve accessibility for people with low
vision and does not limit accessibility for people who don't use a mouse.

The problem arises when onMouseOver is used for more complicated processes --
for instance, using mouseover on images to pop up descriptive text somewhere
else on the screen, resulting in descriptive text that disappears whenever the
user tries to move their focus to it.

Someone suggested that if the PAGL says not to use onMouseOver we could figure
that intelligent web developers will ignore the guideline in valid
curcomstances. Perhaps it would be better to assume that many readers of the
guidelines will be naive on these issues, and that the guidelines should
specify how the events can be used in a positive way and when they can be
detrimental?

For the UA group, maybe this is an opportunity to think about how to make
'onMouseOver' more generic. Thinking back to our recent discussions of 'Point
of Regard', would a set of 'onRegard' or 'onUserCursor' events be a plausible
superset of 'onMouse' that could be applied to a broader range of interactive
devices?


Charles McCathieNevile wrote:

> The discussion on PAGL was about logical events (those which specified a
> function) as opposed to device-dependent events.
>
> The division below was the list as it stands. It occurred to me that we
> could easily enough add onActivate - corresponding in a mouse interface to
> onClick, and to pressing return to activate the item with focus in a
> keyboard interface.
>
> I'm not sure about the rest, but I suspect that onMouseDown, onMouseUp,
> onKeyDown, onKeyUp and onMouseMove are related to selecting a part of the
> document. In determining how to do that we are likely to sort out the
> relationship between the current device-dependent attributes and new
> 'logical' event triggers that can be triggered from various interfaces (eg
> voice)
>
> Which seems to me to leave onMouseOut and onDblClick out in the cold. One
> of the consequences of this is that we should recommend against using
> those events which we are likely to lose (except for providing 'eye-candy'
> - stuff that has no functional importance) and make suggestions about how
> the rest might be used in the page authoring guidelines. (have i said
> this before on this group? if so, sorry)
>
> Charles McCathieNevile
>
> From: http://lists.w3.org/Archives/Public/w3c-wai-gl/1998OctDec/0029.html
>
> Chris is right, so for the sake of completeness I looked up all the event
> attributes again.  Those which I think are device-dependent, and we should
> recommend not be used are:
>
> onMousedown, onMouseup, onMouseover, onMousemove, onMouseout, onKeydown,
> onKeyup, onKeypress, onClick, onDblclick
>
> Those which seem to be logical events are:
>
> onFocus, onBlur, onSelect, onChange, onSubmit, onReset, onLoad, onUnload.
>
> It should also be possible to define something like 'onActivate' - which
> would be equivalent to onClick for a link, but I guess this belongs to
> other groups.
>
> Charles McCathieNevile

--
  -- Paul Adelson
------
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Received on Thursday, 29 October 1998 11:59:02 GMT

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