Web/API/EventTarget

EventTarget is a DOM interface implemented by objects that can receive events and may have listeners for them.

Element, Document, and Window are the most common event targets, but other objects can be event targets, too. For example XMLHttpRequest, AudioNode, AudioContext, and others.

Many event targets (including elements, documents, and windows) also support setting event handlers via onevent properties and attributes.

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  a:hover text { fill: #0095DD; pointer-events: all;}

Constructor

EventTarget()

Creates a new EventTarget object instance.

Methods

EventTarget.addEventListener()

Registers an event handler of a specific event type on the EventTarget.

EventTarget.removeEventListener()

Removes an event listener from the EventTarget.

EventTarget.dispatchEvent()

Dispatches an event to this EventTarget.

Additional methods in Mozilla chrome codebase

Mozilla includes a couple of extensions for use by JS-implemented event targets to implement onevent properties.

See also WebIDL bindings.

• void setEventHandler(DOMString type, EventHandler handler) '
• EventHandler getEventHandler(DOMString type) '

Example

Simple implementation of EventTarget

var EventTarget = function() {
  this.listeners = {};
};

EventTarget.prototype.listeners = null;
EventTarget.prototype.addEventListener = function(type, callback) {
  if (!(type in this.listeners)) {
    this.listeners[type] = [];
  }
  this.listeners[type].push(callback);
};

EventTarget.prototype.removeEventListener = function(type, callback) {
  if (!(type in this.listeners)) {
    return;
  }
  var stack = this.listeners[type];
  for (var i = 0, l = stack.length; i < l; i++) {
    if (stack[i] === callback){
      stack.splice(i, 1);
      return;
    }
  }
};

EventTarget.prototype.dispatchEvent = function(event) {
  if (!(event.type in this.listeners)) {
    return true;
  }
  var stack = this.listeners[event.type].slice();

  for (var i = 0, l = stack.length; i < l; i++) {
    stack[i].call(this, event);
  }
  return !event.defaultPrevented;
};

Specifications

Specification	Status	Comment
DOMThe definition of 'EventTarget' in that specification.	Living Standard	No change.
Document Object Model (DOM) Level 3 Events SpecificationThe definition of 'EventTarget' in that specification.	Obsolete	A few parameters are now optional (listener), or accepts the null value (useCapture).
Document Object Model (DOM) Level 2 Events SpecificationThe definition of 'EventTarget' in that specification.	Obsolete	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
EventTarget	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 6	Opera Full support 7	Safari Full support 1 Notes' Full support 1 Notes' Notes' window.EventTarget did not exist on versions of Safari before 10.1.	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1 Notes' Full support 1 Notes' Notes' window.EventTarget did not exist on versions of Safari iOS before 10.3.	Samsung Internet Android Full support 1.0
EventTarget() constructor	Chrome Full support 64	Edge Full support ≤79	Firefox Full support 59	IE No support No	Opera Full support 51	Safari Full support 14	WebView Android Full support 64	Chrome Android Full support 64	Firefox Android Full support 59	Opera Android Full support 47	Safari iOS Full support 14	Samsung Internet Android Full support 9.0
addEventListener	Chrome Full support 1 Notes' Full support 1 Notes' Notes' Before Chrome 49, the type and listener parameters were optional.	Edge Full support 12	Firefox Full support 1	IE Full support 9 Full support 9 No support 6 — 11 Notes' Alternate Name' Notes' Older versions of IE supported an equivalent, proprietary EventTarget.attachEvent() method. Alternate Name' Uses the non-standard name: attachEvent	Opera Full support 7	Safari Full support 1	WebView Android Full support 1 Notes' Full support 1 Notes' Notes' Before Chrome 49, the type and listener parameters were optional.	Chrome Android Full support 18 Notes' Full support 18 Notes' Notes' Before Chrome 49, the type and listener parameters were optional.	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0 Notes' Full support 1.0 Notes' Notes' Before Samsung Internet 5.0, the type and listener parameters were optional.
dispatchEvent	Chrome Full support 4	Edge Full support 12	Firefox Full support 2	IE Full support 9 Full support 9 No support 6 — 11 Notes' Alternate Name' Notes' Older versions of IE supported an equivalent, proprietary EventTarget.fireEvent() method. Alternate Name' Uses the non-standard name: fireEvent	Opera Full support 9	Safari Full support 3.2	WebView Android Full support 4	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 3	Samsung Internet Android Full support 1.0
removeEventListener	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 9 Full support 9 No support 6 — 11 Notes' Alternate Name' Notes' Older versions of IE supported an equivalent, proprietary EventTarget.detachEvent() method. Alternate Name' Uses the non-standard name: detachEvent	Opera Full support 7	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

No support  

No support

See implementation notes.'

See implementation notes.

Uses a non-standard name.'

Uses a non-standard name.

See also

• Event reference - the events available in the platform.
• Event developer guide
• Event interface

EventTarget by Mozilla Contributors is licensed under CC-BY-SA 2.5.