var NN4 = false;
var NN6 = false;
var IE = false;
var Win = false;
var Mac = false;

if ((navigator.appName == "Netscape") && parseInt(navigator.appVersion) < 5) {NN4 = true;}
if ((navigator.appName == "Netscape") && parseInt(navigator.appVersion) >= 5) {NN6 = true;}
if (navigator.userAgent.indexOf("MSIE") > -1) {IE = true;}
if (navigator.platform.indexOf("Win") > -1) {Win = true;}
if (navigator.platform.indexOf("Mac") > -1) {Mac = true;}

var NN = NN4 || NN6;