I've created this service to connect to polygon network. It is a plug and play script to import on HTML file.
<script src="https://cdn.jsdelivr.net/npm/[email protected]/web3-use-polygon.min.js"></script>
NOTE: Remember to also import Web3:
<script src="https://cdn.jsdelivr.net/gh/ethereum/web3.js/dist/web3.min.js"></script>