Javascript preload images for css background-image change

Question

I am developing a website which requires the background image of a div to change on hover of a link.

The way it works is by:

Answer 1

Stack your images as one image, and then add a class that shifts the image's background property to the appropriate offset.

Not only does this turn multiple images into one HTTP request, it also means you don't have to bother writing code to preload the hover state of the images.

This is called a sprite sheet.