In this video i will talk about Object Oriented Programming before ES6 (JavaScript). With the basics out of the way, we'll now focus on object-oriented JavaScript (OOJS) — this video presents a basic view of object-oriented programming (OOP) theory, then explores how JavaScript emulates object classes via constructor functions, and how to create object instances. As JavaScript is widely used in Web Development, in this article we would explore some of the Object Oriented mechanism supported by JavaScript to get most out of it. Some of the common interview question in JavaScript on OOPS includes,- “How Object-Oriented Programming is implemented in JavaScript? How they differ from other languages?