MouseEvent: relatedTarget 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 MouseEvent.relatedTarget read-only property is the secondary target for the mouse event, if there is one.

That is:

Event name target relatedTarget
mouseenter The EventTarget the pointing device entered to The EventTarget the pointing device exited from
mouseleave The EventTarget the pointing device exited from The EventTarget the pointing device entered to
mouseout The EventTarget the pointing device exited from The EventTarget the pointing device entered to
mouseover The EventTarget the pointing device entered to The EventTarget the pointing device exited from
dragenter The EventTarget the pointing device entered to The EventTarget the pointing device exited from
dragleave The EventTarget the pointing device exited from The EventTarget the pointing device entered to

For events with no secondary target, relatedTarget returns null.

FocusEvent.relatedTarget is a similar property for focus events.

Value

An EventTarget object or null.

Examples

Try moving your mouse cursor into and out of the red and blue boxes.

HTML

html
<body id="body">
  <div id="outer">
    <div id="red"></div>
    <div id="blue"></div>
  </div>
  <p id="log"></p>
</body>

CSS

css
#outer {
  width: 250px;
  height: 125px;
  display: flex;
}

#red {
  flex-grow: 1;
  background: red;
}

#blue {
  flex-grow: 1;
  background: blue;
}

#log {
  max-height: 120px;
  overflow-y: scroll;
}

JavaScript

js
const mouseoutLog = document.getElementById("log"),
  red = document.getElementById("red"),
  blue = document.getElementById("blue");

red.addEventListener("mouseover", overListener);
red.addEventListener("mouseout", outListener);
blue.addEventListener("mouseover", overListener);
blue.addEventListener("mouseout", outListener);

function outListener(event) {
  let related = event.relatedTarget ? event.relatedTarget.id : "unknown";

  mouseoutLog.innerText = `\nfrom ${event.target.id} into ${related} ${mouseoutLog.innerText}`;
}

function overListener(event) {
  let related = event.relatedTarget ? event.relatedTarget.id : "unknown";

  mouseoutLog.innerText = `\ninto ${event.target.id} from ${related} ${mouseoutLog.innerText}`;
}

Result

Specifications

Specification
UI Events
# dom-mouseevent-relatedtarget

Browser compatibility

BCD tables only load in the browser

See also