On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 27 on 2013-05-21
In Chrome Android version 27 on 2013-05-22
In Edge version 12 on 2015-07-29
In Firefox version 1 on 2004-11-09 Note: From Firefox 1 to Firefox 3, ch was the width of the M character. From Firefox 1 to Firefox 3, ch did not work with border-width and outline-width CSS properties.
In Firefox for Android version 4 on 2011-03-29
In Internet Explorer version 9 on 2011-03-14
In Quest Browser version 5.0 on undefined
In Opera version 15 on 2013-07-02
In Opera Android version 15 on 2013-07-08
In Safari version 7 on 2013-10-22
In Safari on iOS version 7 on 2013-09-18
In Samsung Internet version 1.5 on 2013-09-25
In WebView Android version 4.4 on 2013-12-09
In WebView on iOS version 7 on 2013-09-18