p5.js

p5.js is a library that lets you use programming to make drawings among many other things.

Taken from the p5.js website:

p5.js is a JavaScript library for creative coding, with a focus on making coding accessible and inclusive for artists, designers, educators, beginners, and anyone else! p5.js is free and open-source because we believe software, and the tools to learn it, should be accessible to everyone.

P5.js Tutorials