On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 1 on 2008-12-11
In Chrome Android version 18 on 2012-06-27
Not in Deno
In Edge version 12 on 2015-07-29
In Firefox version 1 on 2004-11-09 Note: From version 4 to 24, this property could give a wrong value before page load in certain circumstances (see bug 641188).
In Firefox for Android version 4 on 2011-03-29 Note: Before version 24, this property could give a wrong value before page load in certain circumstances (see bug 641188).
In Internet Explorer version 9 on 2011-03-14
In Quest Browser version 5.0 on undefined
In Opera version 9 on 2006-06-20
In Opera Android version 10.1 on 2010-11-09
In Safari version 3 on 2007-10-26
In Safari on iOS version 1 on 2007-06-29 Note: This property returns the width of the visual viewport instead of the layout viewport. See bug 174362 for details.
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 1 on 2007-06-29 Note: This property returns the width of the visual viewport instead of the layout viewport. See bug 174362 for details.