crossorigin is an attribute that set the mode of the request to an HTTP CORS Request.
Its value defines further the CORS policy.
It can be used on every html elements that fetch resources from a cross-origin Url.
With the script element
<script
src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"
integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
crossorigin="anonymous"
defer="true">
</script>
where:
<tag crossorigin=value/>
where:
If the attribute is missing, the CORS request has the No CORS mode.