jQuery is a fast, small, and feature-rich JavaScript library. It simplifies HTML document traversal, event handling, and animation, making it easier to develop web applications. jQuery allows developers to write less code while achieving more functionality, particularly for DOM manipulation, event handling, and AJAX requests.

Although JavaScript has evolved with new features like querySelector and fetch, jQuery remains popular for projects requiring backward compatibility with older browsers. It streamlines tasks like DOM manipulation and simplifies complex JavaScript actions, making it an excellent tool for both beginners and experienced developers.