var FOI = {
  init : 
    function(){   
            
           //add hover effects to top menu (not possible through css because images
           //should be chosen by editor)              
           $("#topmenu img").addEvent("mouseover", FOI.menuHoverEffect);  
           $("#topmenu img").addEvent("mouseout", FOI.menuHoverEffect);                
               
    }, 
    menuHoverEffect : 
        function(e){
        
           var newImg = this.className;
           var oldImg = this.src;
             
           this.src = newImg; 
		   this.className = oldImg;
           
      }
   } 
   
   
 DOMAssistant.DOMReady(FOI.init);