Hovering updating Texture

I have been looking at the following example:
https://stemkoski.github.io/Three.js/Mouse-Over.html

Instead of changing color, I would like to change the texture in a similar way.
I tried using material.map=loader.load( src ), but I can get it right.

Any suggestions? thanks

You also have to set material.map.needsUpdate = true when changing the texture.