function PopupPdf() {
  var w = 300;
  var h = 300;
  var l = Math.floor((screen.width-w)/2);
  var t = Math.floor((screen.height-h)/2);
  window.open("pdf.php","","width=" + w + ",height=" + h + ",top=" + t + ",left=" + l + ",resizable=no,menubar=no,toolbar=no,scrollbars=yes,locations=no,status=no");
}