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


var altKeyPressed = instanceOfKeyboardEvent.altKey


<title>altKey example</title>

<script type="text/javascript">

function showChar(e){
    "Key Pressed: " + String.fromCharCode(e.charCode) + "\n"
    + "charCode: " + e.charCode + "\n"
    + "ALT key pressed: " + e.altKey + "\n"


<body onkeypress="showChar(event);">
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.


Specification Status Comment
Document Object Model (DOM) Level 3 Events Specification
The definition of 'KeyboardEvent.altkey' in that specification.
Obsolete Initial definition.

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See also

Document Tags and Contributors

 Contributors to this page: libbymc, cvrebert, fscholz, teoli
 Last updated by: libbymc,