Open Source HTML5 Charts & Graphs – Flotr2
The library is framework independent and has support for line, bar, candle, pie and bubble charts.
There are lots of customization options offered like the ability to define titles, subtitles, colors, labels on/off and so many others for each and every possible variable.
Flotr2 outputs are interactive, they can be set to respond to the actions of the user. And, they can be extended with plugins (there are already several ones that can add interactions, new decorations, etc.).
Charts and graphs work in all major browsers (including IE6) and they are mobile compatible.