Is there a website or game in which you can play two player battle on the same computer ?

Question

i want to play 2 player battle in which I can chose my team

Answer 1

The easiest way would be to use Pokemon Showdown as you can freely choose among any Pokemon and easily set up battles.

Source: http://replay.pokemonshowdown.com/pokemondatabase-randombattle-13034

Bare in mind you have to use two different internet browsers or PS will detect you as the same person, even if you are in separate windows.