I found some good javascript libraries for PBBG or any kind of web development.

This one is a graphics library useful for drawing vector graphics to the browser. Works great, just remember to set the position:relative value of the DIV you wish to draw in. :)

DHTML: Draw Line, Ellipse, Oval, Circle, Polyline, Polygon, Triangle with JavaScript

This site has a collection of useful libraries for all manner of web related activities.

Javascript Toolbox: Reusable Libraries And Scripts Plus Information