A simple definition of the popular OS and browsers on JS
npm i detectos.js
bower i detectos.js
https://raw.githubusercontent.com/1000tech/detectOS.js/master/detectOS.js
console.log("We know your browser – it's " + Detect.browser + " " + Detect.version);
console.log("We know your OS – it's " + Detect.OS);
console.log("We know everything about you.");
Used on MobiDevices