var popup_window = null;

  function popup(status,url) {

     if(status != 0) {

        if(popup != null) popup.OnTopWindow();

        else {

           var popup = open(url, "Popup", "width=550,height=630,resizable=yes,scrollbars=yes,scrolling=yes");

           popup_window = popup;

        }

     } else {

<!--        if(popup_window != null) popup_window.close();  -->


     }

  }