MouseEvent: movementY 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 movementY read-only property of the MouseEvent interface provides the difference in the Y 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.movementY = currentEvent.screenY - previousEvent.screenY.

Warning: Browsers use different units for movementY and screenY than what the specification defines. Depending on the browser and operating system, the movementY 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.innerText = `movement: ${event.movementX}, ${event.movementY}\n${log.innerText}`;
}

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

Result

Specifications

Specification
Pointer Lock 2.0
# dom-mouseevent-movementy

Browser compatibility

BCD tables only load in the browser

See also