browser = navigator.appName;
os = navigator.platform;
ie = "Microsoft Internet Explorer";
netscape = "Netscape";
mac = "MacPPC"

if(browser == netscape && os != mac) {
   document.write('<link rel=stylesheet type="text/css" href="../pc_nn.css" title=master>');
} else if(browser == netscape && os == mac) {
   document.write('<link rel=stylesheet type="text/css" href="../mac_nn.css" title=master>');
} else if(browser == ie && os == mac) {
   document.write('<link rel=stylesheet type="text/css" href="../mac_ie.css" title=master>');
} else {
   document.write('<link rel=stylesheet type="text/css" href="../pc_ie.css" title=master>');
}