What is core JavaScript language?

Core JavaScript is the basis of the JavaScript language. JavaScript is a dynamic computer programming language. It is lightweight and most commonly used as apart from web pages, whose implementations allow a client-side script to interact with the user and make dynamic pages.

The JavaScript language has the following components: 

Core JavaScript:

Core JavaScript is the basic of the JavaScript language supports both the client and server side.

Client-side javascript (CSJS)

The client-side JavaScript has core JavaScript elements.  For functioning, it also has properties and methods, which helps developers.

Server-side JavaScript (SSJS) 

Server-side JavaScript, as the name suggests runs on server-side. The core is part of client-side as well as server-side JavaScript. It includes the core JavaScript elements.