This is how you use the back and go method of the window's history property to imitate the back button, next button or even go back or forth a few entries in the browsers history.
// does the same thing as your back button: window.history.back(); //does the same: window.history.go(-1); //takes you three documents back in history: window.history.go(-3); // takes you 2 documents forward in history window.history.go(2);