activateMenu = function(nav) {

/* currentStyle restricts the Javascript to IE only */
if (document.all &&
document.getElementById(nav).currentStyle) {  
var navroot = document.getElementById(nav);
        
/* Get all the list items within the menu */
var lis=navroot.getElementsByTagName("LI");  
for (i=0; i<lis.length; i++) {
        
/* If the LI has another menu level */
if(lis[i].lastChild.tagName=="UL"){
            
/* assign the function to the LI */
lis[i].onmouseover=function() {	
                
/* display the inner menu */
this.lastChild.style.display="block";
}
lis[i].onmouseout=function() {   
this.lastChild.style.display="none";
}
}
}
}
}
window.onload= function(){
 /* pass the function the id of the top level UL */

/* remove one, when only using one menu */
activateMenu('nav');  
}