function popup(mylink, windowname, width, height)
      {
        if (! window.focus)return true;
        var href;
        if (typeof(mylink) == 'string')
          href=mylink;
        else
          href=mylink.href;
        window.open(href, windowname, 'width=' + width + ',height=' +height+ ',scrollbars=no');
        return false;
      }