92811 Tweak Chess Javascript

Attached is javascript for a script that lets me demonstrate chess moves, positions, tactics, etc on projector. It works ok except that original pre-game setup is only from the white side. I want to sometimes show a game from the black side. I want you to tweak the script so that I can flip the board upside down to show from black side. Note that double click brings pieces to side of board so maybe a keystroke combination could do this, or a button off to the side?