On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 5 on 2010-05-25
In Chrome Android version 18 on 2012-06-27
Not in Deno
In Edge version 12 on 2015-07-29
In Firefox version 6 on 2011-08-16 Note: Apart from firing the event on window as other browsers do, Firefox also fires the event on the document object. See bug 1228802. Before Firefox 24, the interface for this event is a plain Event, not FocusEvent.
In Firefox for Android version 6 on 2011-08-16 Note: Apart from firing the event on window as other browsers do, Firefox for Android also fires the event on the document object. See bug 1228802. Before Firefox for Android 24, the interface for this event is a plain Event, not FocusEvent.
In Internet Explorer version 11 on 2013-10-17
In Quest Browser version 5.0 on undefined
In Opera version ≤12.1 on undefined
In Opera Android version ≤12.1 on undefined
In Safari version 5.1 on 2011-07-20
In Safari on iOS version 5 on 2011-10-12
In Samsung Internet version 1.0 on 2013-04-27
In WebView Android version 4.4 on 2013-12-09
In WebView on iOS version 5 on 2011-10-12