function menu() {

  if (document.all && document.getElementById) {

      mm = document.getElementById("mainnav");

      for (i=0; i<mm.childNodes.length; i++) {

          node = mm.childNodes[i];

       //   if (node.nodeName=="LI") {

              node.onmouseover=function() {

                  this.className+=" over";

                  //alert(this.className);

              }

              node.onmouseout=function(){

                  this.className=this.className.replace(" over", "")

              }

     //     }

      }

  }

}