function pmufr_open_popup(purl, pname, pwidth, pheight) {
  var top=(screen.height-pheight)/2;
  var left=(screen.width-pwidth)/2;
  var MyWindow = window.open(purl, pname, "resizable=no,scrollbars=no,status=no,menubar=no,directories=no,location=no,top="+top+",left="+left+",width=" + pwidth + ",height=" + pheight + ",closed=no,opener=no");
  }