Do you miss something on BrainKing.com and would you like to see it here? Post your request into this board! If there is a more specific board for the request, (i.e. game rule changes etc) then it should be posted and discussed on that specific board.
Is Fischer Random chess here? Is it like normal chess but instead each colours back row of pieces are resorted randomly and each side's setup is different. I think there are also different castling rules. I think chessbase.com have the low down.
But then the positins are pre-defined. Also, could you put more functionality in the javascript so you could view your score against each opponent or view your games by opponent?