The MouseEvent.screenX read-only property provides the horizontal coordinate of the mouse pointer in global (screen) coordinates.


var pixelNumber = instanceOfMouseEvent.screenX

Return value

  • pixelNumber is the offset from the left side of the screen in pixels.


<title>screenX\screenY example</title>

<script type="text/javascript">

function showCoords(evt){
    "screenX value: " + evt.screenX + "\n"
    + "screenY value: " + evt.screenY + "\n"


<body onmousedown="showCoords(event)">
<p>To display the mouse coordinates click anywhere on the page.</p>

When you trap events on the window, document, or other roomy elements, you can get the coordinates of that event (e.g., a click) and route it properly, as the following example demonstrates:

function checkClickMap(e) {
  if (e.screenX < 50) doRedButton();
  if (50 <= e.screenX && e.screenX < 100) doYellowButton();
  if (e.screenX >= 100) doRedButton();


Specification Status Comment
Document Object Model (DOM) Level 3 Events Specification
The definition of 'MouseEvent.screenX' in that specification.
Working Draft No change from Document Object Model (DOM) Level 2 Events Specification.
Document Object Model (DOM) Level 2 Events Specification
The definition of 'MouseEvent.sceenX' in that specification.
Recommendation Initial definition

Browser compatibility

Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
Basic support (Yes) (Yes) 6 (Yes) (Yes)
Feature Firefox Mobile (Gecko) Android IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API CSSOM View DOM Events MouseEvent Property Read-only Reference Référence