ROLL OVER MENU in client side how?

[solidcodes]

I know how to make a ROLL OVER MENU, but the problem is the image is loading
from the server side.

What i want is to put all the images into memory of computer of the client so that when the client hover the mouse the images is not fetch from the server but from on the client side.

for example this one.
http://www.drwbarker.com

-is this they called caching?

thanks in advance.

[Pepejeria]

[solidcodes]

Thank you VERY MUCH man!

[eldacar]

There's no need to use javascript at all :
http://alistapart.com/articles/sprites