function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

var startList = function(myE) {
if (document.all&&document.getElementById) {
navRoot = document.getElementById(myE);
for (var 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", "");
   }
   }
  }
 }
}

addLoadEvent(function() {startList("nav")});