What Is ReactJS? Complete Beginner's Guide with Examples (2026)

If you've started learning web development, you've probably come across ReactJS. It's one of the most popular technologies used to build modern websites and web applications. From social media platforms to online shopping websites, ReactJS powers many of the fast and interactive experiences we use every day. But what exactly is ReactJS, and why do developers prefer it over traditional methods? What Is ReactJS? ReactJS, commonly known as React, is a free and open-source JavaScript library develop