MouseEvent: altKey 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.altKey read-only property is a boolean value that indicates whether the alt key was pressed or not when a given mouse event occurs.

Be aware that the browser can't always detect the alt key on some operating systems. On some Linux variants, for example, a left mouse click combined with the alt key is used to move or resize windows.

Note: On Macintosh keyboards, this key is also known as the option key.

Value

A boolean value, where true indicates that the key is pressed, and false indicates that the key is not pressed.

Examples

This example logs the altKey property when you trigger a click event.

HTML

html
<p>Click anywhere to test the <code>altKey</code> property.</p>
<p id="log"></p>

JavaScript

js
let log = document.querySelector("#log");
document.addEventListener("click", logKey);

function logKey(e) {
  log.textContent = `The alt key is pressed: ${e.altKey}`;
}

Result

Specifications

Specification
UI Events
# dom-mouseevent-altkey

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
altKey

Legend

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

Full support
Full support

See also