snifferjs/src/run.js

Browser/engine/os/device detection tool

//expose sniff results of current UserAgent and install `html` tag classes
var Sniff = Sniffer(navigator.userAgent),
    htmlNode = document.getElementsByTagName('html')[0],
    classNameArr = [htmlNode.className];

Sniff.browser.name && classNameArr.push(Sniff.browser.name);
Sniff.browser.engine && classNameArr.push(Sniff.browser.engine);
Sniff.os.name && classNameArr.push(Sniff.os.name);

for (var prop in Sniff.features) {
    if (Sniff.features[prop]) classNameArr.push(prop);
}

htmlNode.className = classNameArr.join(' ');

if (typeof(module) != 'undefined' && module.exports) {
    module.exports = Sniff;
}
else {
    global.Sniff = Sniff;
}