Yeah, [according to MDN](https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Using_full_screen_mode?redirectlocale=en-US&redirectslug=Web%2FGuide%2FDOM%2FUsing_full_screen_mode#BrowserCompatibility) there is no significant difference in support. (They have another chart somewhere which says only Firefox supports fullscreenEnabled, but current Chrome does as well so probably they just forgot to update that one for a long time.)

Note that it is (at the moment) mozFullScreenEnabled but webkitFullscreenEnabled... web standards are fun. Probably best to check both. (Actually, it would be nice to check for the ~10 possible combinations at a single place, and then simply store the function names as variables. That would deuglify non-initialization parts of the code a bit.)