MouseEvent: movementX property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The movementX read-only property of the MouseEvent interface provides the difference in the X coordinate of the mouse pointer between the given event and the previous mousemove event. In other words, the value of the property is computed like this: currentEvent.movementX = currentEvent.screenX - previousEvent.screenX.

Warning: Browsers use different units for movementX and screenX than what the specification defines. Depending on the browser and operating system, the movementX units may be a physical pixel, a logical pixel, or a CSS pixel. You may want to avoid the movement properties, and instead calculate the delta between the current client values (screenX, screenY) and the previous client values.

Value

A number. Always zero on any MouseEvent other than mousemove.

Examples

This example logs the amount of mouse movement using movementX and movementY.

HTML

html
<p id="log">Move your mouse around.</p>

JavaScript

js
function logMovement(event) {
  log.insertAdjacentHTML(
    "afterbegin",
    `movement: ${event.movementX}, ${event.movementY}<br>`,
  );
  while (log.childNodes.length > 128) log.lastChild.remove();
}

const log = document.getElementById("log");
document.addEventListener("mousemove", logMovement);

Result

Specifications

Specification
Pointer Lock 2.0
# dom-mouseevent-movementx

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
movementX

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Requires a vendor prefix or different name for use.
Has more compatibility info.

See also