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