Protovis, the free and open-source visualisation JavaScript library has been replaced by D3 a new visualisation library with improved support for animations and interactions.
http://mbostock.github.io/protovis
Protovis is no longer under development.
The final release of Protovis was v3.3.1 (4.7 MB). The Protovis team is now developing a new visualization library, D3.js, with improved support for animation and interaction. D3 builds on many of the concepts in Protovis; for more details, please read the introduction and browse the examples
This project was led by Mike Bostock and Jeff Heer of the Stanford Visualization Group, with significant help from Vadim Ogievetsky. We welcome your comments and suggestions.