KeyboardEvent.altKey

The KeyboardEvent.altKey read-only property is a boolean value that indicates if the alt key (Option or ⌥ on OS X) was pressed (true) or not (false) when the event occurred.

Syntax

var altKeyPressed = instanceOfKeyboardEvent.altKey

Return value

A boolean value

Examples

<html>
<head>
<title>altKey example</title>

<script type="text/javascript">

function showChar(e){
  alert(
    "Key KeyDown: " + String.fromCharCode(e.charCode) + "\n"
    + "charCode: " + e.charCode + "\n"
    + "ALT key KeyDown: " + e.altKey + "\n"
  );
}

</script>
</head>

<body onkeydown="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
UI Events # dom-keyboardevent-altkey

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`altKey`	1	12	1.5	9	≤12.1	≤4	≤37	18	4	≤12.1	≤3	1.0