var mlist_req_win;
function mlist_req(target)
{
  if (mlist_req_win) {
    mlist_req_win.close();
  }
  url = 'mlist_req.php?tid='+target;
  args = 'left=20,top=20,width=450,height=520,toolbar=0,menubar=0,status=1,dependent=1,alwaysRaised=1,scrollbars=1,resizable=0';
  mlist_req_win = window.open(url, '_blank', args);
  mlist_req_win.focus();
}