this library based on d3 in also nice:
a chart-library based on d3:
https://naver.github.io/billboard.js/
what's really neat about it is the possibility to set up the code online.
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for fast graphics a tool like datawrapper.com is really cool
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For really simple graphs you can even use hypes paths:
https://www2.aachener-zeitung.de/zva/karlo/test/revealSVGPathStrokeDashGap/