where we use js code in shopify code example
Example: how to add jquery to shopify
<!-- Include jQuery in your theme.liquid file, between <head> tag -->
<head>
<script
src="https://code.jquery.com/jquery-3.4.1.js"
integrity="sha256-WpOohJOqMqqyKL9FccASB9O0KwACQJpFTUBLTYOVvVU="
crossorigin="anonymous">
</script>
</head>