I would imagine your game would have two frames (one hidden frame), and the hidden
frame would contain scripts to check and update page.
In the bottom frame i see you might have two choices:
1. have a meta refresh which checks every 5 (or so) secs if a move has been made, and
if detects a move, sends a refresh command to the top frame
2. have a php script which continually checks if a move has been made ( using sleep()
browser, then continue detecting if changes have been made......
the implications of #2 (i would image), is the explorer icon will be constantly
loading a page, so if you click stop, the game will cease
hope that helps