There are many browsers, and there are engines. I heard that you need to not support browsers and their engines, but it is not clear how to check what the engine supports some kind of specification ?
If to support only the engine, not the browsers, it turns out that, if webkit supports what the w3c and other browsers, will automatically begin to maintain, or not ? (and here I do not quite understand How the engine and the browser affect what is the specification ?)