squares

[Endeavor88]

http://endeavor.aspfreeserver.com/dhtml/squares/

can someone tell me why these squares stop before reaching 100 movements?

(try clicking on the button a million times)

[Endeavor88]

it's weird.
the squares are supposed to do 10 movements, but sometimes a square does 1 movement, 2, 3, or even about 13....