if (document.images)
   {
     image_off= new Image(48,26);
     image_off.src="/images/header/home_off.gif";  

     image_on= new Image(48,26);
     image_on.src="/images/header/home_on.gif"; 
   }

function change1(picName,imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + ".src");
      document[picName].src= imgOn;
    }
 }