This is a partially complete webpage. unpkg.com/react in the browser returns https://unpkg.com/react@17.0.2/index.js just look at unpkg.com/react/rect@17.0.2/ click on umd copy link address for react.production.min.js place this inside the < script > attribute Note: the script needs a "crossorigin" attribute

default seems to be port 8000 python -m http.server python -m http.server 3000