WOW.js

Reveal animations when you scroll. Easily customize animation settings like style, delay, length, offset, iterations, etc. By default, you can use it to trigger animate.css animations. But you can easily change the settings to your favorite animation library. Smaller than other JavaScript parallax plugins, like Scrollorama (they do fantastic things, but can be too heavy for simple needs). Super simple to install, and works with animate.css, so if you already use it, that will be very fast to setup. Fast execution and lightweight code, the browser will like it. It just take seconds to install and use WOW.js! Once purchased on UpLabs, you’ll receive a commercial license PDF and be all set to use WOW.js in your commercial applications. If you want to use WOW.js to develop commercial sites, themes, projects, and applications, the Commercial license is the appropriate license. With this option, your source code is kept proprietary.