The MouseEvent.altKey
read-only property is a Boolean
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.
Syntax
var altKeyPressed = instanceOfMouseEvent.altKey
Return value
A Boolean
, where true
indicates that the key is pressed, and false
indicates that the key is not pressed.
Example
This example logs the altKey
property when you trigger a click
event.
HTML
<p>Click anywhere to test the <code>altKey</code> property.</p> <p id="log"></p>
JavaScript
let log = document.querySelector('#log'); document.addEventListener('click', logKey); function logKey(e) { log.textContent = `The alt key is pressed: ${e.altKey}`; }
Result
Specifications
Specification | Status | Comment |
---|---|---|
Document Object Model (DOM) Level 3 Events Specification The definition of 'MouseEvent.altkey' in that specification. |
Obsolete | No change from Document Object Model (DOM) Level 2 Events Specification. |
Document Object Model (DOM) Level 2 Events Specification The definition of 'MouseEvent.altkey' in that specification. |
Obsolete | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
altKey | Chrome Full support Yes | Edge Full support 12 | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support