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/DOM

MouseEvent.altKey

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

Browser compatibility

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) ? ? ? ? ?

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/altKey