Script.aculo.us: The Script.aculo.us library can be found at the website of the same name: http://script.aculo.us. Their tagline is “it’s about the user interface, baby!” which accurately describes their focus. Script.aculo.us is built on top of the Prototype library and picks up where it stops. It includes functionality for adding drag-and-drop support to an application. It has a lot of effects code for fading, shrinking, moving, and otherwise animating DOM elements. Script.aculo.us also has a slider control and a library for manipulating lists of elements.