Rickshaw
JavaScript toolkit for creating interactive real-time graphs
...Customize all you like with techniques you already know. Rickshaw is free and open source, available under the MIT license. Developed at Shutterstock. Rickshaw relies on the fantastic D3 visualization library to do lots of the heavy lifting for stacking and rendering to SVG. Some extensions require jQuery and jQuery UI, but for drawing some basic graphs you'll be okay without. Rickshaw uses jsdom to run unit tests in Node to be able to do SVG manipulation. As of the jsdom 7.0.0 release, jsdom requires Node.js 4 or newer jsdom changelog.