Browsers and Rendering engines Each property and unit was tested in the latest version of each of the major rendering engines – Presto, WebKit, Gecko and Trident. The browsers used in the charts above were as follows: Presto 2.2 Tested using Opera 10 beta 3 Presto 2.4 Tested using Opera 10.5 pre alpha. This uses Presto 2.5, but the support for Backgrounds and Borders is the same as Presto 2.4 WebK