What is a JavaScript Framework and What Does it Do?

A web development framework is an abstraction in which software providing generic functionality can be selectively changed by additional user-written code. A JavaScript framework is an application framework written in JavaScript, 

where programmers can manipulate the functions and use them for their convenience. It is a collection of JavaScript code libraries that provide a web developer with pre-written code for routine programming tasks. Frameworks are structures with a particular context and help you create web applications within that context. 

It is completely possible to build strong web applications without JavaScript frameworks, but frameworks provide a template that handles common programming patterns. Frameworks are more adaptable for web design, and hence most website developers take to them. Frameworks make working with JavaScript easier and smoother, offering such possibilities as making applications device responsive.

JavaScript is a steadfast choice for web development and many of its frameworks revolve around this undertaking.