As far as I know, standard JavaScript has no way to get at the ::before or ::after pseudo-elements. Element.children doesn't let you get to it.
I know there has to be a way, at least in Chrome-privileged Firefox add-on code, since it lists every ::before element in the page (and apparently getComputedStyle() works on it too, as you can list all styles of it in inspector, which is written in JavaScript).
Where is this API documented, and is it something that's different and privileged-only in say Firefox and Chrome browser, or something that is on track to be standard soon?