// PC
if (navigator.appVersion.indexOf("Win") != -1 ) {
        // Netscape
        if (navigator.appName == "Netscape")
                document.write("<link rel='stylesheet' href='../css/netscape_pc.css' type='text/css'>");
        // IE
        else if (navigator.appName == "Microsoft Internet Explorer")
                document.write("<link rel='stylesheet' href='../css/ie_pc.css' type='text/css'>");

// Mac
} else if (navigator.appVersion.indexOf("Mac") != -1 ) {
        // Netscape
        if (navigator.appName == "Netscape")
                document.write("<link rel='stylesheet' href='../css/netscape_mac.css' type='text/css'>");
        // IE
        else if (navigator.appName == "Microsoft Internet Explorer")
                document.write("<link rel='stylesheet' href='../css/ie_pc.css' type='text/css'>");

} else
        document.write("<link rel='stylesheet' href='../css/ie_pc.css' type='text/css'>");