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

Syntax

var pixelNumber = instanceOfMouseEvent.screenX

Return value

double floating point value. Early versions of the spec defined this as an interger referring to the number of pixels. See the Browser compatibility section for details.

Example

<html>
<head>
<title>screenX\screenY example</title>

<script type="text/javascript">

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

</script>
</head>

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

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();
}

Specifications

Specification Status Comment
CSS Object Model (CSSOM) View Module
The definition of 'screenX' in that specification.
Working Draft Redefines MouseEvent from long to double. 
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 Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) 6 (Yes) (Yes)
Redefined from long to double 56 ? ? ? ? ?
Feature Android Webview Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Redefined from long to double 56 56 ? ? ? ? ?

See also

Document Tags and Contributors

 Contributors to this page: jpmedley, libbymc, bertyhell, cvrebert, teoli, judemelancon, kscarfone, Jeremie
 Last updated by: jpmedley,