// Javascript to rollover the "Back" and "Next" arrows in the tour

   var nextArrow=new Image;
   var backArrow=new Image;
   var firsArrow=new Image;
   var nextBrrow=new Image;
   var backBrrow=new Image;
   var firsBrrow=new Image;

   nextArrow.src="images/next.gif";
   backArrow.src="images/back.gif";
   firsArrow.src="images/firs.gif";
   nextBrrow.src="images/nexton.gif";
   backBrrow.src="images/backon.gif";
   firsBrrow.src="images/firson.gif";

   function backstd() {
      document.back.src=backArrow.src;
      return;
   }

   function nextstd() {
      document.next.src=nextArrow.src;
      return;
   }
 
  function firsstd() {
      document.firs.src=firsArrow.src;
      return;
   }

   function backon() {
      document.back.src=backBrrow.src;
      return;
   }

   function nexton() {
      document.next.src=nextBrrow.src;
      return;
   }

   function firson() {
      document.firs.src=firsBrrow.src;
      return;
   }