A JS Library For Manipulating Data-Driven Documents – D3
It can help us visualizing the data as HTML or SVG quickly, handle interactivity, and incorporate smooth transitions + staged animations into web pages.
The library can be used as a visualization framework (like Protovis) or as a framework to build pages (like jQuery).
D3 is not the traditional visualization framework that comes with it limits and ready-to-use templates. Rather, it solves only the crux of the problem: efficient manipulation of documents based on data which ends up in a serious flexibility.