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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.
Working Draft Initial definition.

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

Document Tags and Contributors

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