CDNオンリーでReactを動かしてみた - Qiita

<script crossorigin src="https://unpkg.com/react@18/umd/react.production.min.js"></script> <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"></script> <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script> <div id="root"></div> <script type="text/babel"> let dom = document.querySelector("#root"); const { useEffect } = React; const App = () =