Random Cursor Images with Javascript

I have a div in the middle of a simple webpage. When I hover this div, I want my cursor to change randomly to a customized image. I know how to set my own cursor image with css. But how to use javascript to make this cursor image different each time we refresh the page?

This website shows exactly what I want to achieve. When we hover an image, the cursor becomes a little icon that is different each time we refresh the page. http://ift.tt/1OpX61W

Thanks in advance.