Java Script is a computer language mostly associated with client-side development on web browsers.
Interactive web pages on the internet use Java Script as their programming language. As such, it is widely used with WebRTC to develop the client side.
Recently, Java Script has been introduced as part of the server side development with the development of Node.js. This makes it possible to code using a single language both the client side and the server side of a web application in general and of WebRTC services specifically.