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
In Edge version 12 on 2015-07-29
In Firefox version 1 on 2004-11-09 Note: Before Firefox 44, position: fixed didn't create a stacking context in most cases. Firefox and the specification have been modified to mimic Chrome and Safari's long-time behavior.
In Firefox for Android version 4 on 2011-03-29 Note: Before Firefox for Android 44, position: fixed didn't create a stacking context in most cases. Firefox for Android and the specification have been modified to mimic Chrome and Safari's long-time behavior.
In Internet Explorer version 7 on 2006-10-18 Note: In Internet Explorer, fixed positioning doesn't work if the document is in quirks mode.
In Quest Browser version 5.0 on undefined
In Opera version 4 on 2000-06-28
In Opera Android version 14 on 2013-05-21
In Safari version 1 on 2003-06-23
In Safari on iOS version 1 on 2007-06-29
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