Webpage Lab
Lets you instantly experiment with HTML, CSS, and JavaScript.
Galois Script
A language for large integers and modular math in Galois fields.
JS
CodeBox
Turns HTML textareas and inputs into code editors (syntax coloring, etc).
JS
IceView
Handles the math for a standard 2D or 3D viewer (pan, zoom, rotate) with both touch and mouse support.
JS
Color Dialog
Creates color-picker dialogs that can be attached to HTML elements.