There is no bundle.js file and this file is included inside index.html. This is why the example doesn't work.

I did exact steps as mentioned in readme:

Clone this repo https://github.com/blocknative/web3-onboard.git Navigate to the project directory: cd examples/with-vanilla-js Install the dependencies: npm install Run the development server: npm run dev 

Still there is no bundle.js file that is included in index.html
<script defer src="dist/bundle.js"></script>