Until late 1942, the United States was not in the war as an active participant, though they were indirectly supporting their allays. In late 1941, Japan decided to give them a run by attacking Pearl Habour so that Japan can expand its control in Asia to Pacific whereas German is extending its powers through Europe. Japan wanted to destroy US Aircraft carriers so that they can get control of the pacific. However, on that day aircraft carriers were not in the port. After the Pearl Habour attack, the US wanted to give it back to Japan by attacking Tokoyo which they did successfully.
Pearl Harbor Attack: Reference www.atomicheritage.org
Then Japan decided that they have to destroy the aircraft carrier which was escaped during the last attack. Japanese admiral, Yamamoto planed for a trap by attacking Midway island which is somewhat mid between Japan and the USA. Yamamoto divided his troops into three. First troops have to attack the bases in Midway, while his air troops will destroy the US aircraft carriers which will come rescue.
But,
this plan was de-coded by the US naval intelligence in Pearl Harbour. So the USA moved his troops close to the Midway way before the arrival of Japan's troops. Also, they had another set of troops waiting for Japan's arrivals.
Though the Japanese are more superior than the US naval troops, they were able to withstand the Japan attack, mainly due to the fact that the US was able to decode the encrypted messages of Japan communication.
