loadTopMenu = function() 
{       
if (document.all&&document.getElementById) 
 {              
  menunavParent = document.getElementById("nav");       
       
   for (x=0; x < menunavParent.childNodes.length; x++) 
     {              
        menunode = menunavParent.childNodes[x];
                     
           if (menunode.nodeName=="LI") 
             {                     
              menunode.onmouseover=function() 
                {                            
                this.className+=" over";                     
                }                     
                menunode.onmouseout=function() 
                {                            
                  this.className=this.className.replace(" over", "");
         }
           }
        }
     }
}

window.onload=loadTopMenu;