This behavior was based on the cool button script but it has been rewritten to use the power of DHTML behaviors. Since I haven't explained much about behaviors before I think it is about time to do so now. if you don't want to read about how this behavior was made jump straight down to the demo section. Behavior pros and cons The only real negative thing about behaviors is that it is an IE5 only technology but besides that it is all good. A very good thing about behaviors is that they are extremely easy to reuse and all you have to do is to add the behavior in the style declaration.