Flotr 
Posted on 31 luglio 2008
JavaScript Plotting Library
Flotr is a javascript plotting library based on the Prototype Javascript Framework (version 1.6.0.2 at the moment) and inspired by Flot (written by Ole Laursen). Flotr enables you to draw appealing graphs in most modern browsers with an easy to learn syntax. It comes with great features like legend support, negative value support, mouse tracking, selection support, zoom support, event hooks, CSS styling support and much more.