Bas Wenneker has written Plotr, a charting engine in Prototype that uses canvas. Example PLAIN TEXT JAVASCRIPT:   var dataset = {                 'myFirstDataset': [[0, 1], [1, 0.8], [2, 2.3], [3, 1.3], [4, 2.56]],                 'mySecondDataset': [[0, 0.5], [1, 0.5], [2, 2], [3, 1], [4, 1.4]]

SpiderMonkey is a JavaScript interpreter, compiler, and decompiler that is used in Firefox, as well as other Mozilla projects and derivatives and Yahoo’s Yahoo! Widgets. UOX3, an Ultima Online emulator also uses it. SpiderMonkey is written in C and was first authored by Brendan Eich for the Netscape browser. SpiderMonkey is complemented at the Mozilla Foundation by the Rhino project, which also implements a JavaScript interpreter, compiler and decompiler, except in Java instead of C.