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">
function showChar(e){
alert(
"Key Pressed: " + String.fromCharCode(e.charCode) + "\n"
+ "charCode: " + e.charCode + "\n"
+ "ALT key pressed: " + e.altKey + "\n"
);
}
</script>
</head>
<body onkeypress="showChar(event);">
<p>
Press any character key,
with or without holding down the ALT key.<br />
You can also use the SHIFT key together with the ALT key.
</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
We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
| Feature | Edge | Firefox (Gecko) | Chrome | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
| Feature | Edge | Firefox Mobile (Gecko) | Android | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | (Yes) | ? | ? | ? | ? | ? |