Actually, he CAN'T survive outside of the tank. His skin will dry out, and then his internal organs will start to dry out. However, you do have longer to find him than you would a fish, since he can and does breathe air, so he won't suffocate outside of water.
Any tank with a frog or anything that jumps should be fully covered, without any holes, to prevent this kind of thing.
Edit: Looking at the time, he's probably already dead unless you found him....