What React Is and Why It Is Used

Web applications need to respond to user actions such as clicking buttons, submitting forms, and updating content without reloading the page. As interfaces grow, managing these updates with plain JavaScript becomes complex and difficult to maintain.

Instead of manually selecting elements and updating them, React uses components, small, reusable pieces of the interface. Each component represents a part of the UI and updates only when needed. React focuses only on the user interface layer. It works alongside HTML, CSS, and JavaScript, helping organize code in a more structured and scalable way.

This approach makes applications easier to build, maintain, and extend. React is widely used in real-world products, from simple tools to large web applications.

Before working with Next.js, it is important to understand how React works. Next.js is built on top of React and uses the same concepts, such as components, props, and state, to build applications.