On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 48 on 2016-01-20
In Chrome Android version 48 on 2016-01-26
In Edge version 12 on 2015-07-29
In Firefox version 41 on 2015-09-22 Note: Firefox 42 added support for bidirectional and RTL scripts in vertical modes.
In Firefox for Android version 41 on 2015-09-22 Note: Firefox for Android 42 added support for bidirectional and RTL scripts in vertical modes.
In Internet Explorer version 9 on 2011-03-14 Note: Internet Explorer's implementation differs from the specification. Internet Explorer's implementation differs from the specification.
In Quest Browser version 5.0 on undefined
In Opera version 35 on 2016-02-02
In Opera Android version 35 on 2016-02-04
In Safari version 10.1 on 2017-03-27
In Safari on iOS version 10.3 on 2017-03-27
In Samsung Internet version 5.0 on 2016-12-15
In WebView Android version 48 on 2016-01-26
In WebView on iOS version 10.3 on 2017-03-27