Expanding list menus - help

I am trying to create a menu which expands from a bullet point list, so when you click on the main list a sub list appears between the two elements of the main list. any ideas?

Does cold fusion do this or would I need some kind of onClick javaScript?

 

I think you will find what your looking for here.
http://www.dynamicdrive.com/dynamicindex1/index.html

 

thank you that was great