function sniff() {
var agt=navigator.userAgent.toLowerCase();
var bmajor = parseInt(navigator.appVersion);
if (((agt.indexOf("msie")!=-1) &&  (bmajor < 4)) || ((agt.indexOf("msie")==-1) && (bmajor <=4))) {
alert('Greetings from the Board on Life Sciences of the National Academies.\n\nIt appears that you might be using an older Web browser. We have made a concerted effort to provide all of our users to all of the information published on this Web site. However, this site has been optimized for newer browsers.\n\nIf you have questions or comments, please contact us: http://dels.nas.edu/bls/contact.shtml. Thank you for visiting our Web site.');
}
}