if (navigator.userAgent.indexOf("Mac") != -1) {
    if (navigator.appName.indexOf('Netscape') != -1) {
        document.write("<link rel='stylesheet' href='/css/mac-ns.css' type='text/css'>");
    }
    else {
        document.write("<link rel='stylesheet' href='/css/mac-ie.css' type='text/css'>");
    }
}
else if (navigator.userAgent.indexOf('Win') != -1) {
    if (navigator.appName.indexOf('Netscape') != -1) {
        document.write("<link rel='stylesheet' href='/css/win-ns.css' type='text/css'>");
    }
    else {
        document.write("<link rel='stylesheet' href='/css/win-ie.css' type='text/css'>");
    }
}
else {
    document.write("<link rel='stylesheet' href='/css/win-ie.css' type='text/css'>");
}

