var popupwin = null;

  function popup(loc,ww,hh)

   {

    var mywidth = (ww + 0);

    var myheight = (hh + 0);

    var myspecs = "'menubar=0,status=1,resizable=1,location=0,titlebar=1,toolbar=0,scrollbars=1,width=" + mywidth + ",height=" + myheight + "'";

      if (popupwin == null || popupwin.closed)

			{

            popupwin = window.open (loc, 'popupwin', myspecs);

           }

		 else

		   {

            popupwin.focus();

            popupwin.location.href = loc;

          }

    }