On the standards track: Yes
Is Experimental: No
Is Deprecated: No
Not in Chrome
Not in Chrome Android
Not in Edge
In Firefox version 1 on 2004-11-09
In Firefox for Android version 4 on 2011-03-29
In Internet Explorer version 5 on 1999-03-18
Not in Quest Browser
In Opera version 8 on 2005-04-19
In Opera Android version 10.1 on 2010-11-09
In Safari version 1 on 2003-06-23
In Safari on iOS version 1 on 2007-06-29
Not in Samsung Internet
Not in WebView Android