Hi,
Please remember that thsi is a PhP forum..
Anyway. the trick you saw there is done with a combination of javascript and css. When you click an element, this function is called:
<SCRIPT language=JavaScript>
function exd(o){
d = document.getElementById("gd" + o)
i = document.getElementById("pl" + o)
if(d.className=="gd"){
d.className="gde"
i.src="images/m.gif"}
else{
d.className="gd"
i.src="images/p.gif"
}
(Yes, i copied it from their source code).
J.