startList = function() {
 var navItems = document.getElementById("header").getElementsByTagName("div");
 for (var i=0; i<navItems.length; i++) {
	navItems[i].onmouseover=function() { this.className += " over"; }
  navItems[i].onmouseout=function() { this.className = ""; }
 }
}
window.onload=startList;