Can xdotool be used on some window not in the front?

On Ubuntu desktop, can I use xdotool to mouse click (e.g. click a link) and press some keys (e.g. Ctrl+s) on a window (e.g. Firefox's window) that is not in the front, so that I can work on another different window which may need to lie on top of the other windows, while at the same time, let xdotool to work on a hidden window? Thanks.