activateMenu = function(nav) {

	if (document.all && document.getElementById(nav).currentStyle) {  
        var navroot = document.getElementById(nav);
        
        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'); 
}