The MouseEvent interface represents events that occur due to the user interacting with a pointing device (such as a mouse). Common events using this interface include click, dblclick, mouseup, mousedown.

MouseEvent derives from UIEvent, which in turn derives from Event. Though the MouseEvent.initMouseEvent() method is kept for backward compatibility, creating of a MouseEvent object should be done using the MouseEvent() constructor.

Several more specific events are based on MouseEvent, including WheelEvent and DragEvent.

Constructor

MouseEvent()
Creates a MouseEvent object.

Properties

This interface also inherits properties of its parents, UIEvent and Event.

MouseEvent.altKey Read only
Returns true if the alt key was down when the mouse event was fired.
MouseEvent.button Read only
The button number that was pressed (if applicable) when the mouse event was fired.
MouseEvent.buttons Read only

The buttons being depressed (if any) when the mouse event was fired.

MouseEvent.clientX Read only
The X coordinate of the mouse pointer in local (DOM content) coordinates.
MouseEvent.clientY Read only
The Y coordinate of the mouse pointer in local (DOM content) coordinates.
MouseEvent.ctrlKey Read only
Returns true if the control key was down when the mouse event was fired.
MouseEvent.metaKey Read only
Returns true if the meta key was down when the mouse event was fired.
MouseEvent.movementX Read only
The X coordinate of the mouse pointer relative to the position of the last mousemove event.
MouseEvent.movementY Read only
The Y coordinate of the mouse pointer relative to the position of the last mousemove event.
MouseEvent.offsetX Read only
The X coordinate of the mouse pointer relative to the position of the padding edge of the target node.
MouseEvent.offsetY Read only
The Y coordinate of the mouse pointer relative to the position of the padding edge of the target node.
MouseEvent.pageX Read only
The X coordinate of the mouse pointer relative to the whole document.
MouseEvent.pageY Read only
The Y coordinate of the mouse pointer relative to the whole document.
MouseEvent.region Read only
Returns the id of the hit region affected by the event. If no hit region is affected, null is returned.
MouseEvent.relatedTarget Read only

The secondary target for the event, if there is one.

MouseEvent.screenX Read only
The X coordinate of the mouse pointer in global (screen) coordinates.
MouseEvent.screenY Read only
The Y coordinate of the mouse pointer in global (screen) coordinates.
MouseEvent.shiftKey Read only
Returns true if the shift key was down when the mouse event was fired.
MouseEvent.which Read only
The button being pressed when the mouse event was fired.
MouseEvent.mozPressure Read only
The amount of pressure applied to a touch or tablet device when generating the event; this value ranges between 0.0 (minimum pressure) and 1.0 (maximum pressure).
MouseEvent.mozInputSource Read only

The type of device that generated the event (one of the MOZ_SOURCE_* constants listed below). This lets you, for example, determine whether a mouse event was generated by an actual mouse or by a touch event (which might affect the degree of accuracy with which you interpret the coordinates associated with the event).

MouseEvent.webkitForce Read only
The amount of pressure applied when clicking
MouseEvent.x Read only
Alias for MouseEvent.clientX.
MouseEvent.y Read only
Alias for MouseEvent.clientY

Constants

MouseEvent.WEBKIT_FORCE_AT_MOUSE_DOWN Read only
Minimum force necessary for a normal click
MouseEvent.WEBKIT_FORCE_AT_FORCE_MOUSE_DOWN Read only
Minimum force necessary for a force click

Methods

This interface also inherits methods of its parents, UIEvent and Event.

MouseEvent.getModifierState()
Returns the current state of the specified modifier key. See the KeyboardEvent.getModifierState() for details.
MouseEvent.initMouseEvent()
Initializes the value of a MouseEvent created. If the event has already being dispatched, this method does nothing.

Example

This example demonstrates simulating a click (that is programmatically generating a click event) on a checkbox using DOM methods. 

function simulateClick() {
  var evt = new MouseEvent("click", {
    bubbles: true,
    cancelable: true,
    view: window
  });
  var cb = document.getElementById("checkbox"); //element to click on
  var canceled = !cb.dispatchEvent(evt);
  if(canceled) {
    // A handler called preventDefault
    alert("canceled");
  } else {
    // None of the handlers called preventDefault
    alert("not canceled");
  }
}
document.getElementById("button").addEventListener('click', simulateClick);
<p><label><input type="checkbox" id="checkbox"> Checked</label>
<p><button id="button">Click me</button>

Click on the button to see how the sample works:

Specifications

Specification Status Comment
CSS Object Model (CSSOM) View Module
The definition of 'MouseEvent' in that specification.
Working Draft Redefines MouseEvent from long to double. This means that a PointerEvent whose pointerType is mouse will be a double.
Pointer Lock
The definition of 'MouseEvent' in that specification.
Candidate Recommendation From Document Object Model (DOM) Level 3 Events Specification, added movementX and movementY properties.
CSS Object Model (CSSOM) View Module
The definition of 'MouseEvent' in that specification.
Working Draft From Document Object Model (DOM) Level 3 Events Specification, added offsetX and offsetY, pageX and pageY, x, and y properties. Redefined screen, page, client and coordinate (x and y) properties as double from long.
Document Object Model (DOM) Level 3 Events Specification
The definition of 'MouseEvent' in that specification.
Obsolete From Document Object Model (DOM) Level 2 Events Specification, added the MouseEvent() constructor, the getModifierState() method and the buttons property.
Document Object Model (DOM) Level 2 Events Specification
The definition of 'MouseEvent' in that specification.
Obsolete Initial definition.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes Yes Yes Yes Yes
MouseEvent() constructor47 ?11 No Yes Yes
altKey Yes Yes Yes Yes Yes Yes
button1 Yes1

9

Yes1

Yes3.1
buttons43 Yes Yes29 Yes No
clientX Yes Yes Yes6 Yes Yes
clientY Yes Yes Yes6 Yes Yes
ctrlKey Yes Yes Yes Yes Yes Yes
getModifierState47 Yes ? ? ? ?
initMouseEvent Yes Yes Yes ? Yes ?
metaKey Yes Yes Yes Yes Yes Yes
movementX

37

22 — 37 webkit

Yes

41

1 — 41 moz

No ? No
movementY

37

22 — 37 webkit

Yes

41

1 — 41 moz

No ? No
offsetX Yes Yes396 Yes Yes
offsetY Yes Yes396 Yes Yes
pageX45 Yes Yes9 Yes Yes
pageY45 Yes Yes9 Yes Yes
region Yes3 ?304 No No No
relatedTarget Yes Yes48 Yes Yes Yes
screenX Yes Yes Yes6 Yes Yes
screenY Yes Yes Yes6 Yes Yes
shiftKey Yes Yes Yes Yes Yes Yes
which1 Yes15951
x Yes Yes536 Yes Yes
y Yes Yes536 Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes Yes Yes Yes ?
MouseEvent() constructor4747 ?14 Yes Yes ?
altKey ? ? Yes ? ? ? ?
button ? ? Yes ? ? ? ?
buttons No No Yes ? ? No ?
clientX Yes Yes Yes Yes Yes Yes ?
clientY Yes Yes Yes Yes Yes Yes ?
ctrlKey ? ? Yes ? ? ? ?
getModifierState4747 Yes ? ? ? ?
initMouseEvent Yes Yes Yes Yes Yes ? ?
metaKey ? ? Yes ? ? ? ?
movementX37

37

Yes — 37 webkit

Yes

41

4 — 41 moz

? No ?
movementY37

37

Yes — 37 webkit

Yes

41

4 — 41 moz

? No ?
offsetX Yes Yes Yes43 ? ? ?
offsetY Yes Yes Yes43 ? ? ?
pageX4545 Yes ? ? ? ?
pageY4545 Yes ? ? ? ?
region No No ?304 No No ?
relatedTarget ? ? Yes ? ? ? ?
screenX Yes Yes Yes Yes Yes Yes ?
screenY Yes Yes Yes Yes Yes Yes ?
shiftKey ? ? Yes ? ? ? ?
which Yes Yes Yes45 Yes Yes ?
x ? ? Yes53 ? ? ?
y ? ? Yes53 ? ? ?

1. Different convention used prior to version 9.

2. Resrictions apply depending on OS.

3. This feature is behind the Experimental Web Platform Features preference (needs to be set to true). To change preferences in Chrome, visit chrome://flags.

4. From version 30: this feature is behind the canvas.hitregions.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

5. On mousemove events, the which property is incorrectly always set to 1.

See also