How can I know in my triggering code that preventDefault had been called?
$(document).trigger('customEvent', params);
if (/* ??? */)
doDefaultActions();
views:
363answers:
5
A:
To my knowledge the "preventDefault()" call is about preventing the native browser responses to things like clicks on anchor tags or keypresses in text fields. Once the event handling cycle is over, it's over. For made-up events, I don't think it has any effect at all since it's all about the jQuery event processing system and not about native browser functionality.
Your code could set some sort of flag somewhere in order to communicate with the "outside world."
[edit] ooh you could try having the handler stash a reference to the event object somewhere that the exteral code can find it, and then externally check with "isDefaultPrevented()". I don't know whether that'd work however.
Pointy
2010-02-09 14:19:07
A:
If your custom event is really custom, then what are you trying to prevent? Normally preventDefault is used so that the browser won't do its normal thing. The browser itself doesn't know or care about custom events.
quixoto
2010-02-09 14:20:10
One reason it might be useful is when you've got a handler bound to both a real event and a custom event. That's nice when you need to initialize a system from (say) the initial state of a checkbox. You don't want to trigger the "click" handler because you don't want the checkbox to toggle. Thus he might want to know if during that sort of process something decided to cancel the checkbox toggle. (The handler wouldn't necessarily check the event name.)
Pointy
2010-02-09 14:23:22
Good point(y)..
quixoto
2010-02-10 06:39:33
+1
A:
If you're asking how to find out whether or not the default has been prevented, use:
event.isDefaultPrevented()
This will return 'true' or 'false' based on whether or not preventDefault() was called.
patrick dw
2010-02-09 14:23:25
+10
A:
trigger() can also take an event object, so if you can create an event object, like so:
var event = jQuery.Event("customEvent");
$(document).trigger(event);
then you can check after the trigger to see if preventDefault() has been called like so:
var prevented = event.isDefaultPrevented();
Dave Van den Eynde
2010-02-09 14:26:20
Yeah I learned it myself today by looking it up on the jQuery API. So we all learn today!
Dave Van den Eynde
2010-02-09 14:39:19
That doesn't appear to be documented (at api.jquery.com at least) - well I can't find it anyway. The docs are a little better now but I still wish they'd make it a wiki. [edit: ok I see it in the source now!!]
Pointy
2010-02-09 14:44:32
http://api.jquery.com/trigger/ and checkout the first comment. "Documented" is perhaps not the right word here, but it sure is there.
Dave Van den Eynde
2010-02-09 14:49:46
A:
Custom events do not have some default actions that happens .. (they are custom).
On the other hand, if you want to stop the bubbling effect of this event to others then have a look at triggerHandler which does not bubbles up to the hierarchy ..
Gaby
2010-02-09 14:26:54