JavaScript is a lightweight and dynamic programming language. It allows us to implement complex features on web pages. JavaScript also supports object-oriented concepts. It was designed to create network-centric applications.It is an interpreted, full-fledged programming language. According to Stack Overflow Developer Survey 2020, 95% of all the websites use JavaScript.
The most used website like Google is built using JS. Other websites too like YouTube, Facebook, Twitter, etc are built using JS.
jQuery
jQuery is a popular JavaScript library that simplifies working with HTML documents, handling events, animating elements, and making AJAX requests, among other things. It is widely famous for its philosophy of “Write less, do more”.
AJAX (Asynchronous JavaScript and XML) is a technique used in web development to send and receive data from a server asynchronously without requiring a page reload.