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 integer 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.
Obsolete 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.
Obsolete Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes Yes6 Yes Yes
Value type changed from long to double56 ? ? ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes Yes Yes Yes ?
Value type changed from long to double5656 ? ? ? ? ?

See also

Document Tags and Contributors

Last updated by: fscholz,