[Javascript] Want to trap both click and double-click

[paul at juniperwebcraft.com (Paul Novitski)]

>On Mon, 18 Dec 2006 17:01:46 -0800 Paul Novitski wrote:
>Is the ondblclick event not well-supported cross-browser?

At 12/19/2006 06:07 AM, Mike Dougherty wrote:
>[iirc] the last time I looked at it, the 
>dblclick method was an IE extension and is not supported by Fx.


Here's a little research I did this morning, not 
yet backed up by personal experimention with event handlers:

On Peter-Paul Koch's mouse events page 
<http://www.quirksmode.org/js/events_mouse.html> 
there's a demo that shows the following events firing on double-click:

         mousedown
         mouseup
         click
         mousedown
         mouseup
         click
         dblclick

(I get identical results in both Firefox 2.0 and IE 6.)

That is to say, both clicks are registered 
singly, then dblclick is added to the pile once 
the system has had a chance to measure the 
interval between the clicks.  Therefore in order 
for dblclick to predominate it needs to cancel 
any conflicting click, mousedown, and mouseup 
events using a method such as the delay Mike described on December 18th.

Koch comments:
         "The dblclick event is rarely used. Even 
when you use it, you should be sure never to 
register both an onclick and an ondblclick event 
handler on the same HTML element. Finding out 
what the user has actually done is nearly impossible if you register both.
         "After all, when the user double?clicks 
on an element one click event takes place before 
the dblclick. Besides, in Netscape the second 
click event is also separately handled before the 
dblclick. Finally, alerts are dangerous here, too.
         "So keep your clicks and dblclicks well 
separated to avoid complications."
http://www.quirksmode.org/js/events_mouse.html#dblclick

dblclick is listed in the Mozilla Developer 
Center's Gecko DOM Reference 
<http://developer.mozilla.org/en/docs/DOM:element.ondblclick> 
as an element event, with the footnote, "DOM 
Level 0. Not part of specification."

from <http://www.w3.org/TR/DOM-Level-2-Events/glossary.html#dt-DOM-Level-0>:
         The term "DOM Level 0" refers to a mix 
(not formally specified) of HTML document 
functionalities offered by Netscape Navigator 
version 3.0 and Microsoft Internet Explorer 
version 3.0. In some cases, attributes or methods 
have been included for reasons of backward compatibility with "DOM Level 0".

On the Event Listener page, dblclick is not listed:
http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-eventgroupings-mouseevents-h3

Instead, the initMouseEvent event has a detailArg 
parameter, defined as "Specifies the Event's mouse click count."

Perhaps it was decided that, rather than treating 
double-click as a special case, it would be 
better to devise a general system for responding 
to N number of clicks to accommodate future GUI conventions more naturally.

However, for what it's worth, it does appear that 
contemporary browsers do still have dblclick in their event vocabulary.

Regards,
Paul