This script needs the JS module Velocity to work, so since there is no packaging in this project, you have to call it from your HTML page, like that:

<script src="//cdnjs.cloudflare.com/ajax/libs/velocity/2.0.6/velocity.min.js"></script>

Place your images in the images folder. Prefer very small GIF or PNG image files.

Configuration is to be made in a JSON file following the example config file config.json with the right paths to your images. The configuration file needs to be called from the HTML page after Velocity is called:

<script src="config.js"></script>

Then you also need to call the main script from your webpage

<script src='animated_background.js'></script>

Finally, place an empty HTML wrapper with the id animated-background-wrapper in your HTML, outside of your content:

<div id="animated-background-wrapper"></div>

You're done!