MyNewWindow = null;

function popup(url, name, or_size, ve_size)
{
  if (MyNewWindow && !MyNewWindow.closed)
    { MyNewWindow.close();
	}
    settings=
             "toolbar=no,location=no,directories=no,"+
             "status=no,menubar=no,scrollbars=yes,"+
             "resizable=no,width="+ or_size +
             ",height=" + ve_size +
             ","+
             "top=100,left=100";

//MyNewWindow=window.open('/montagna/popup/'+url,name,settings)
MyNewWindow=window.open(url,name,settings)
MyNewWindow.focus();
}