Clipboard not defined

This is my code, nothing else:

<script src="https://cdn.jsdelivr.net/clipboard.js/1.5.12/clipboard.min.js"></script>
<script>
    new Clipboard('.cbcopy');
</script>

Result: Uncaught ReferenceError: Clipboard is not defined

EDIT: Meanwhile I found the hidden complete example: https://github.com/zenorocha/clipboard.js/blob/master/demo/constructor-selector.html#L18 Result is the same: Clipboard is not defined

EDIT 2: Now I found that the error only occurs when the code is loaded via AJAX. If called directly, it works. So maybe it’s no bug at all and just a matter of correct code placement. Sorry if it’s just my fault.