Garrett Smith wrote:
On Thu, Sep 24, 2009 at 12:02 AM, Mike Wilson <[email protected]> wrote:
Yes, the base for event delegation is certainly something
like that. I just wanted to make clear that the main reason
for adding this functionality (IMO) is event delegation.
I'll let event delegation library creators chime in on the
details on what is needed for making really efficient
behavioural/delegation implementations, and judge the merits
of various optimizations. There has f ex already been mention
of caching "parsed" selectors.
The benefit to that is that the selector text is parsed once, so
something like:-
document.onmouseover = function(ev) {
if(ev.target.matchesSelector(".infotip")) { /*...*/ }
};
could probably be made more efficient as:-
var selector = QuerySelector.create(".infotip");
document.onmouseover = function(ev) {
if(selector.matches(ev.target)) { /*...*/ }
};
I would be surprised if an implementation didn't create an internal
lookup table keyed off the selector text.
