function bookmark(url, sitename)
{
  ns="Firefox, Opera and Netscape users please press CTRL+D on keyboard to bookmark this site."
  if ((navigator.appName=='Microsoft Internet Explorer') &&
    (parseInt(navigator.appVersion)>=4))
  {
    window.external.AddFavorite(url, sitename);
  }
  else if (navigator.appName=='Netscape' || 'Opera')
  {
    alert(ns);
  }
}