Check useragent or platform of client navigator and apply it on body

app.js

var platform = {
        ipad: /iPad/.test(navigator.userAgent) && !window.MSStream,
        ios: /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream,
        safari: navigator.userAgent.indexOf('Safari') !== -1 && navigator.userAgent.indexOf('Chrome') === -1 && !window.MSStream,
        mac: navigator.platform.toLowerCase().indexOf('mac') >= 0 && !window.MSStream,
        android: /(android)/i.test(navigator.userAgent) || navigator.platform.toLowerCase().indexOf("android") > -1 && !window.MSStream,
        firefox: navigator.userAgent.toLowerCase().indexOf('firefox') > -1 && !window.MSStream,
        windows: navigator.platform.indexOf('Win') > -1 && !window.MSStream,
        ie: !!window.MSInputMethodContext && !!document.documentMode && !window.MSStream
    };

for(key in platform) {
    document.body.classList.toggle(key, platform[key]);
}