function popup(url, name, popw, poph, parm) {
  var w = screen.width;
  var h = screen.height;

  if (popw == undefined) {
    popw=640;
  }

  if (poph == undefined) {
    poph=480;
  }

  var l = (w-popw)/2, t = (h-poph)/2;

  if (parm == undefined) {
    var w = window.open(url, name, "left="+l+",top="+t+",width="+popw+"+,height="+poph+",fullscreen=no,scrollbars=yes,resizable=yes");
  } else {
    var w = window.open(url, name, "left="+l+",top="+t+",width="+popw+"+,height="+poph+","+parm);
  }

}