GreenSock is a popular JavaScript library used for creating high-performance animations on the web. It allows developers to animate HTML, CSS, SVG, and other web elements easily and efficiently. With its simple syntax and powerful features, GreenSock helps enhance user experiences by making websites more dynamic and engaging. One of the key components of GreenSock is GSAP (GreenSock Animation Platform), which provides a robust set of tools for controlling animations. GSAP is known for its speed and flexibility, making it a favorite among web developers and designers for creating smooth transitions and complex animations without sacrificing performance.