Chart.js

Chart.js is a free open-source JavaScript library for data visualization, which supports 8 chart types: bar, line, area, pie, bubble, radar, polar, and scatter. Created by London-based web developer Nick Downie in 2013, now it is maintained by the community and is the second most popular JS charting library on GitHub by the number of stars after D3.js, considered significantly easier to use though less customizable than the latter. More at Wikipedia