The MouseEvent.region read-only property returns the id of the canvas hit region affected by the event. If no hit region is affected, null is returned.


var hitRegion = instanceOfMouseEvent.region

Return value

A DOMString representing the id of the hit region.


<canvas id="canvas"></canvas>

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

ctx.arc(70, 80, 10, 0, 2 * Math.PI, false);
ctx.addHitRegion({id: "circle"});

canvas.addEventListener("mousemove", function(event){
  if(event.region) {
    console.log("hit region: " + event.region);


Specification Status Comment
WHATWG HTML Living Standard
The definition of 'MouseEvent.region' in that specification.
Living Standard Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes)[1] 30 (30)[2] Not supported Not supported Not supported
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported Not supported 30.0 (30) Not supported Not supported Not supported

[1] This feature is behind a feature flag. Set the flag ExperimentalCanvasFeatures to true to enable it.

[2] This feature is behind a feature preference setting. In about:config, set canvas.hitregions.enabled to true.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.