@ MayJune :
Oh, you are speaking about that .. Why do you need to remove the ';' then ?
Just try to run and then try re-running it. It should run faster.
If you study the java script closely, you will notice that it has a timer that takes care of animation; with an interval 5 ms. When you re-run the code, you add another timer with the same interval, but starting at a different time, so the animation appears to be faster (as the code is executed 2x time instead of 1x, due to double timers).