function bookmark(url, sitename)
{
  ns="Netscape, FireFox and Chrome users, use Ctrl+D to bookmark this site. Safari users, use Cmd+D."
  if ((navigator.appName=='Microsoft Internet Explorer') &&
    (parseInt(navigator.appVersion)>=4))
  {
    window.external.AddFavorite(url, sitename);
  }
  else if (navigator.appName=='Netscape')
  {
    alert(ns);
  }
}