Word of note... You can not set a frames per second nor can you create a way of making it appear to run at a desired frames per second.
The reason is that each computer you run the script on will not run at the same speed. A 3 Ghz processor is faster than a 2 Ghz processor by a factor of 50% or a 1/3rd slower, either way you can not factor in a test for speed.
You could use the CSS3 transition methods, plenty of examples out on the net for that method.