activateMenu = function(nav) {
		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(lis[i].lastChild.tagName=="UL"){
				lis[i].onmouseover=function() {	
					 this.lastChild.style.display="block";
				}
				lis[i].onmouseout=function() {                       
					 this.lastChild.style.display="none";
				}
			}
		}
}
window.onload= function(){
    activateMenu('nav'); 
}