Why did japan launch an attack on u. s. naval forces at pearl harbor?

Attack of Pearl harbour was a surprise attack by Japan navy on US battleships on Pearl Harbour, Hawaii .This incident is also known as the Battle of Pearl harbour.The attack started on 7 December,1941 in the morning and after attacking Hawaii several other attacks were conducted on the same day on other US bases like Guam,Philippines etc. The major reason of attack was to prevent US navy to take action when Japan fights Britain in Southeast Asia.But this attack led US to join WW2 and declare war against Japan