How to dynamically use css with a sprite

How to dynamically use css with a sprite

I am sorry if i am asking a silly question but I really need help with
this. I have a sprite i created dynamically. I understand to show this as
animation i need to change the offsets for the position of this image. I
read you put this into a CSS file. How do i dynamically create this CSS
and use it dynamically using asp.net and c#?
So far i change these offsets using AJAX, a timer and response.write the
DIV. But the image appears to flicker. So, I am hoping that by using CSS
it will eliminate this flickering.
Thanks in hope...