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


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.


<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
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

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support YesEdge Full support YesFirefox Full support YesIE Full support 6Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android ?
Value type changed from long to doubleChrome Full support 56Edge ? Firefox ? IE ? Opera ? Safari ? WebView Android Full support 56Chrome Android Full support 56Edge Mobile ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android ?


Full support  
Full support
Compatibility unknown  
Compatibility unknown

See also

Document Tags and Contributors

Last updated by: fscholz,