var ns=true;
var ie=true;
var browser = navigator.appName;
var agent = navigator.userAgent; 
var IE4 = (document.all) ? true : false;
var NS4 = (document.layers) ? true : false;
var IEStyles = "<LINK REL='stylesheet' title='CSS' HREF='adv_ie.css' TYPE='text/css' media='screen'>"
var NSStyles = "<LINK REL='stylesheet' title='CSS' HREF='adv_ie.css' TYPE='text/css' media='screen'>";
var MacIEStyles = "<LINK REL='stylesheet' title='CSS' HREF='adv_ie.css' TYPE='text/css' media='screen'>"
var MacNSStyles = "<LINK REL='stylesheet' title='CSS' HREF='adv_ie.css' TYPE='text/css' media='screen'>";

if (agent.indexOf("Win") >= 0) { 
if (browser == 'Netscape') ie=false; else ns = false; 
if (ie) document.write(IEStyles); else document.write(NSStyles);
}

else if (agent.indexOf("Mac") >= 0) {
if (browser == 'Netscape') ie=false; else ns = false; 
if (ie) document.write(MacIEStyles); else document.write(MacNSStyles);
}