var startList = function() {
  if (document.all&&document.getElementById) {
    var navRoot = document.getElementById("topMenu");
    var bDiv = document.getElementById("bodyDiv");
    for (i=0; i<navRoot.childNodes.length; i++) {
      var node = navRoot.childNodes[i];
      if (node.nodeName=="LI") {
        node.onmouseover=function() {
          this.className+=" over";
          bDiv.style.zIndex = "-1";
        }
        node.onmouseout=function() {
          this.className=this.className.replace(" over", "");
          bDiv.style.zIndex = "0";
        }
      }
    }
  }
}
window.onload=startList;