function closewin() {
   // close the 'childWin' when the parent browser is closed
   if (childWin != null) {
      if (!childWin.closed) {
         childWin.close();
      }
   }
}

function openwin(destHref) {
   if (typeof(childWin) == "undefined"  || childWin.closed == true ) {
      childWin = window.open("", "childWin", "scrollbars,status,resizable,toolbar,menubar,location");
   } else {
      childWin.focus();
   }  
   window.childWin.location = destHref;
}