iScroll is a high-performance, small-footprint, and dependency-free JavaScript library that enables smooth scrolling and zooming for website content on mobile and desktop devices. It is particularly useful for implementing scrollable regions in web pages, emulating native scrolling, and supporting various interaction features such as scrolling horizontally or vertically, paging, and snapping to content. The library is designed to be lightweight yet powerful, providing a seamless experience across different browsers and platforms.