On May 1, 2006, at 9:18 PM, Boris Zbarsky wrote:
Doug Schepers wrote:
The WebAPI WG would like to solicit feedback about Event Groups,
particularly from implementors. Do Event Groups fill a current
need? Are
they implemented in your UA, or are you planning to do so? Are
they used by
authors in the wild? Basically, are there compelling reasons to
either keep them or to get rid of
them?
The only event groups Gecko implements at the moment are the
"normal" and "system" event groups. The bubbling phase in the
"system" event group is when default actions take place. This can
be used by authors of XBL bindings, for example (and is). Note
that none of this requires actually exposing the system event group
per se; there's just an XBL syntax to add listeners in that group
instead of the "normal" one.
I think this concept of event groups is not the same as the DOM Level
3 Events concept. Event groups in DOM3EV don't result in whole
separate ordered capture and bubble phases. The main effect is that
stopPropagation called in a listener in one group doesn't affect
other groups. However, listeners on a given target all fire before
proceeding to the next step of the bubble/capture phase. Also,
relative ordering of listenrs in different groups are undefined.
Regards,
Maciej
