<!-- 
     if (document.images) { 
     NextOn = new Image(); 
     NextOn.src = "images/next_p.gif";
     NextOff = new Image();
     NextOff.src = "images/next.gif";

     PreviousOn = new Image(); 
     PreviousOn.src = "images/previous_p.gif";
     PreviousOff = new Image();
     PreviousOff.src = "images/previous.gif";

         } 

function turnOn(btnName) 
    {if (document.images) 
      {document [btnName].src = eval(btnName + "On.src");

           } 
       } 

function turnOff(btnName) 
    {if (document.images) 
          {document [btnName].src = eval(btnName + "Off.src"); 
         
           } 
        } 
   // -->