JavaScript is a programming language which can be used on both front end and back end. Its popularity should mainly be attributed to its power in front end side. While people seem not realize its power in back end until the appearance of Node.js. Node.js is a server-side software system designed for writing scalable Internet applications, notably web servers. Programs are written on the server side in JavaScript, using event-driven, asynchronous I/O to minimize overhead and maximize scalability.It was widely known by program...