CODEWITHSUNDEEP
javascripteventsprototypejslistenerobserver-pattern
Keith Bentrup
Keith Bentrup

Reputation: 11995

Update: How to find event listeners on a DOM node in prototype?

I'm looking for an updated answer to this question.

It seems that Event.observers is no longer used (perhaps to avoid memory leaks) in Prototype 1.6+, so how do I track down now what event listeners are attached to an element?

I know Firebug has a "break on next" button, but there are several mouse listeners on the body element that execute before I can get to the behavior that I want on another particular element, so is there some other way?

Upvotes: 7

Views: 6107

Answers (2)

Crescent Fresh
Crescent Fresh

Reputation: 117028

I've update the answer you linked to with more comprehensive Prototype coverage accounting for changes in versions 1.6.0 to 1.6.1.

It got very messy in between there, but 1.6.1 is somewhat clean:

var handler = function() { alert('clicked!') };
$(element).observe('click', handler);

// inspect
var clickEvents = element.getStorage().get('prototype_event_registry').get('click');
clickEvents.each(function(wrapper){
    alert(wrapper.handler) // alerts "function() { alert('clicked!') }"
})

Upvotes: 7

kangax
kangax

Reputation: 39198

Things are now routed through Element storage : )

Element.getStorage(yourElement).get('prototype_event_registry') will give you an instance of Prototype's Hash, so you can do anything that you would do with hash.

// to see which event types are being observed
Element.getStorage(yourElement).get('prototype_event_registry').keys();

// to get array of handlers for particular event type
Element.getStorage(yourElement).get('prototype_event_registry').get('click');

// to get array of all handlers
Element.getStorage(yourElement).get('prototype_event_registry').values();

// etc.

Note that these are undocumented internal details which might be changed in the future, so I wouldn't rely on them except for, perhaps, debugging purposes.

Upvotes: 7

Related Questions