如何优化canvas html5的javascript代码，使其在firefox中运行顺畅?

I have this big problem that when i run this javascript code used in canvas html5 in firefox it lags badly and the images blink, but in google chrome and internet explorer the performance is better. I really need the procedure, so I wont get lost. The code is about projectile motion. I need to mention that i need the conditions im using. (Note: there is a fence function in javascript that i made that makes firefox lag so much to the point that is freezes)I have this big problem that when i run this ja