Question

JavaScript is designed for following purpose

Answer 1

JavaScript is a CS (Client Side) scripting language. It is in no way related to Java as it's name suggests, but it is used for client side scripting. By Client Side scripting, i mean the ability to manipulate data, the DOM and a webpage as a whole, without having a backend service or language.

Answer 2

Javascript is designed to add interactivity to HTML  pages by executing various inbuilt and user defined functions and by performing DOM operations.