Who would win a fight Batman or Superman?

"The fight has already taken place, at the end of "Batman: The Dark Knight Returns" Batman uses a cloud of green Kryptonite gas to rob Superman of his powers, and had no trouble beating him up. Superman can win a fight... but Batman can plan a battle. There's a difference. Superman has called Batman the "most dangerous man alive". "
This post illustriates how batman can beat most versions of superman without prep.

"Superman because because lets face it batman as no superpowers and superman can fly.Beside the fight would go like this-batman would throw something at him then superman will say IM a loser."

While this one illustiates how superman can beat batman if he has no prep.