Ribbons often have a rollover effect; let's duplicate this effect for our ribbon.
Be sure to review the previous recipe as it goes through all the intricacies of the sliding task-bar ribbon used in this example.
What is new in this recipe begins with the comment "// make the growth and shrinkage quick". There are three things that we have to accomplish, the first is placing listening events on the mouseover and mouseout. We use the MooTools custom events mouseenter and mouseleave, which help us avoid event bubbling.