xdrop = function() {
 if (document.all&&document.getElementById) {
  for (n=1;document.getElementById("nav"+n)!=null;n++)
  {
    navRoot = document.getElementById("nav"+n);
    for (i=0; i<navRoot.childNodes.length; i++) {
     node = navRoot.childNodes[i];
     if (node.nodeName=="LI") {
      node.onmouseover=function() {
       this.className+="over";
      }
      node.onmouseout=function() {
       this.className=this.className.replace("over", "");
      }
     }
    }
  }
 }
}
window.onload=xdrop;