AOS

AOS (Animate On Scroll) is a lightweight JavaScript library that triggers CSS animations when elements scroll into the viewport. It allows developers to add smooth fade-in, slide, zoom, and flip effects to page elements as users scroll down the page. AOS uses data attributes on HTML elements to configure animation types, durations, delays, and easing functions without writing JavaScript. The library provides a simple initialization script and supports various animation presets that can be customized through CSS. It includes options for controlling animation behavior such as once-only animations, mirror effects when scrolling up, and anchor placements. AOS is mobile-friendly and performs efficiently by using requestAnimationFrame and debouncing scroll events. The library is popular for creating engaging landing pages, portfolios, and marketing websites with minimal implementation effort.