用于客户端游戏逻辑操作的Webapp安全性

I am working on an in-browser game, taking advantage of the Canvas available in HTML5. However, I realized that I have a big vulnerability in the system. The game score and other statistics about game play are calculated on the client-side in Javascript, then submitted to the server for storage and comparison to other players through XMLHTTPRequest. This obviously exposes the statistics to manipulation and potential cheating.I am working on an in-browser game, taking adva