startList = function() {
  if (document.all&&document.getElementById) {
    var x = document.getElementById('nav');
    if (!x) return;
    var y = x.getElementsByTagName('dd');
    var z = x.getElementsByTagName('li');
    for (var i=0;i<y.length;i++) {
      y[i].onmouseover=function() {
        this.className+=" overr";
      }
      y[i].onmouseout=function() {
        this.className=this.className.replace(" overr", "");
      }
    }
    for (var i=0;i<z.length;i++) {
      z[i].onmouseover=function() {
        this.className+=" overr";
      }
      z[i].onmouseout=function() {
        this.className=this.className.replace(" overr", "");
      }
    }
  }
}
window.onload=startList;