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="inline";
                             }
                        lis[i].onmouseout=function() {
                   this.lastChild.style.display="none";
                        }
           }
        }
}
}
window.onload= function(){
    activateMenu('nav'); /* pass in the id of the top level UL */
}