See demo on Codepen: https://codepen.io/comehope/pen/MGeRRO
Watch interactive screencast on Scrimba: https://scrimba.com/p/pEgDAM/cdKMBTk
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000014599280
Inspired by: Online Tutorials channel https://www.youtube.com/watch?v=npxT2aiQviQ