我可以使用 jQuery 找到绑定在元素上的事件吗？

Question

I bind two event handlers on this link:

<a href='#' id='elm'>Show Alert</a>

JavaScript:

$(function()
{
  $('#elm').click(_f);
  $('#elm').mouseover(_m);
});

function _f(){alert('clicked');}
function _m(){alert('mouse over');}

Is there any way to get a list of all events bound on an element, in this case on element with id="elm" ?

Answer 1

In modern versions of jQuery, you would use the $._data method to find any events attached by jQuery to the element in question. Note , this is an internal-use only method:

// Bind up a couple of event handlers
$("#foo").on({
    click: function(){ alert("Hello") },
    mouseout: function(){ alert("World") }
});

// Lookup events for this particular Element
$._data( $("#foo")[0], "events" );

The result from $._data will be an object that contains both of the events we set (pictured below with the mouseout property expanded):

Then in Chrome, you may right click the handler function and click "view function definition" to show you the exact spot where it is defined in your code.

Answer 2

General case:

• Hit F12 to open Dev Tools
• Click the Sources tab
• On right-hand side, scroll down to Event Listener Breakpoints , and expand tree
• Click on the events you want to listen for.
• Interact with the target element, if they fire you will get a break point in the debugger

Similarly, you can:

• right click on the target element -> select " Inspect element "
• Scroll down on the right side of the dev frame, at the bottom is ' event listeners '.
• Expand the tree to see what events are attached to the element. Not sure if this works for events that are handled through bubbling (I'm guessing not)

Answer 3

I'm adding this for posterity; There's an easier way that doesn't involve writing more JS. Using the amazing firebug addon for firefox ,

1. Right click on the element and select 'Inspect element with Firebug'
2. In the sidebar panels (shown in the screenshot), navigate to the events tab using the tiny > arrow
3. The events tab shows the events and corresponding functions for each event
4. The text next to it shows the function location

Answer 4

You can now simply get a list of event listeners bound to an object by using the javascript function getEventListeners().

For example type the following in the dev tools console:

// Get all event listners bound to the document object
getEventListeners(document);

Answer 5

The jQuery Audit plugin plugin should let you do this through the normal Chrome Dev Tools. It's not perfect, but it should let you see the actual handler bound to the element/event and not just the generic jQuery handler.

Answer 6

Note that events may be attached to the document itself rather than the element in question. In that case, you'll want to use:

$._data( $(document)[0], "events" );

And find the event with the correct selector :

And then look at the handler > [[FunctionLocation]]

Answer 7

While this isn't exactly specific to jQuery selectors/objects, in FireFox Quantum 58.x, you can find event handlers on an element using the Dev tools:

1. Right-click the element
2. In the context menu, Click 'Inspect Element'
3. If there is an 'ev' icon next to the element (yellow box), click on 'ev' icon
4. Displays all events for that element and event handler

Answer 8

I used something like this if($._data($("a.wine-item-link")[0]).events == null) { ... do something, pretty much bind their event handlers again } to check if my element is bound to any event. It will still say undefined (null) if you have unattached all your event handlers from that element. That is the reason why I am evaluating this in an if expression.

Answer 9

When I pass a little complex DOM query to $._data like this: $._data($('#outerWrap .innerWrap ul li:last a'), 'events') it throws undefined in the browser console.

So I had to use $._data on the parent div: $._data($('#outerWrap')[0], 'events') to see the events for the a tags. Here is a JSFiddle for the same: http://jsfiddle.net/giri_jeedigunta/MLcpT/4/