Morris.js is a FREE open-source community maintained project, available under the BSD license, started in 2012 by Olly Smith. Main branch has not been maintained since 2014, but there are many forks with extensions of this project.
Featured Version: 0.5.0
You can download the latest version from GitHub or use a Morris.js CDN. jQuery (version 1.7 or later) and Raphael (version 2.0 or later) are also required.