Anime.js : Anime.js is a fast, multipurpose and lightweight JavaScript animation library with a simple, yet powerful API.
It works with CSS properties, SVG, DOM ...
yepnope.js : A Conditional Loader For Your Polyfills!
DOMAssistant : The modular lightweight JavaScript library, with CSS selectors, event handling, AJAX and complete Unicode support
Zombie.js : Zombie.js is a lightweight framework for testing client-side JavaScript code in a simulated environment. No browser required.
hunt : Library to detect when DOM elements become visible and disappear on scroll.
A passive reconnaissance tool inside the DOM (experimental)
