var images = new Array('/images/hdr_sdn.jpg', '/images/hdr_sdn2.jpg', '/images/hdr_sdn3.jpg', '/images/hdr_sdn4.jpg', '/images/hdr_sdn5.jpg');
  var l = images.length;
  var random_no = Math.floor(l*Math.random());
  document.getElementById("banner").src = images[random_no];