function setNav() {
  if (selected){
	var navItems = document.getElementById('menu_nav').getElementsByTagName('LI');
    for (i=0;i<navItems.length;i++) {
  	  if (navItems[i].getAttribute('id') == selected){
  	    navItems[i].getElementsByTagName('A')[0].className+="selected";
  	  }
    }
  }
}

if ( window.addEventListener ) window.addEventListener( 'load', setNav, false );
else if ( window.attachEvent ) window.attachEvent( 'onload', setNav );