On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 1 on 2008-12-11 Note: The text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In Chrome Android version 18 on 2012-06-27 Note: The text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In Edge version 12 on 2015-07-29
In Firefox version 1 on 2004-11-09
In Firefox for Android version 4 on 2011-03-29
In Internet Explorer version 4 on 1997-09-30
In Quest Browser version 5.0 on undefined Note: The text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In Opera version 7 on 2003-01-28 Note: Since Opera 15, the text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In Opera Android version 11 on 2011-03-22
In Safari version 1 on 2003-06-23 Note: The text-transform property does not work for ::first-line pseudo-elements (also not for the old one-colon syntax). See bug 3409.
In Safari on iOS version 1 on 2007-06-29 Note: The text-transform property does not work for ::first-line pseudo-elements (also not for the old one-colon syntax). See bug 3409.
In Samsung Internet version 1.0 on 2013-04-27 Note: The text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In WebView Android version 4.4 on 2013-12-09 Note: The text-transform property does not work for ::first-line pseudo-elements (nor for the one-colon syntax). See bug 40214861.
In WebView on iOS version 1 on 2007-06-29 Note: The text-transform property does not work for ::first-line pseudo-elements (also not for the old one-colon syntax). See bug 3409.