submitP = new Image();
   submitP.src="images/submit.gif";
   submitPRO = new Image();
   submitPRO.src="images/submit_over.gif";

   submit = new Image();
   submit.src="images/submit.gif";
   submitRO = new Image();
   submitRO.src="images/submit_over.gif";

   next = new Image();
   next.src="images/next.gif";
   nextRO = new Image();
   nextRO.src ="images/next_over.gif";

   back = new Image();
   back.src="images/back.gif";
   backRO = new Image();
   backRO.src ="images/back_over.gif";

   function submit_over(button_id) {
      document.getElementById(button_id).src=eval(button_id+"RO").src;
   }
   function submit_out(button_id) {
      document.getElementById(button_id).src=eval(button_id).src;
   }