This makes the first located frame of the specified page the current frame.
For a page with subframes, the first subframe found in the cache will be the one set.
If you wish to specify a particular subframe to load, you should use the selectframes() command.
If the frame cannot be loaded for any reason, the current frame number will be set to 0. Script processing will continue. You should check the status to see if the frame was reloaded from the cache or not.