The basic action is to navigate to the previously viewed document, similar to the click of the browser's Back button. In Navigator 4 or later, however, you can direct the back( ) method to a specific window or frame, thus bypassing the default behavior of the Back button. For example, repeated calls to parent.otherFrame.history.back( ) eventually run out of history for the frame and then cease to do anything further. On the other hand, repeated calls to top.history.back( ) are the same as clicking the Back button, conceivably backing out of the frameset entirely if it wasn't the first document loaded in the current browser session.