The MouseEvent.altKey read-only property is a Boolean indicates if the alt key was pressed (true) or not (false) when the event occurred.
Syntax
var altKeyPressed = instanceOfMouseEvent.altKey
Examples
<html>
<head>
<title>altKey example</title>
<script type="text/javascript">
document.addEventListener('click', function(e) {
console.log('Is Alt/Option key pressed?', e.altKey);
})
</script>
</head>
<body>
<p>
Click anywhere on the page and open your developer console to see the results.
</p>
</body>
</html>
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.
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | Yes | Yes | Yes | Yes | Yes | Yes |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | ? | ? | Yes | ? | ? | ? | ? |