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) (Yes) (Yes) (Yes)
Feature Firefox Mobile (Gecko) Android IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)

See also

Document Tags and Contributors

Contributors to this page: teoli, judemelancon, kscarfone, Jeremie
Last updated by: teoli,