How to fix 'Uncaught TypeError: Cannot read property 'fn' of undefined'

The error throwing when trying to call jQuery library before bootstrap.js.

To solve the problem you should change as shown below.

<script src="scripts/jquery-3.3.1.min.js"></script>
<script src="scripts/bootstrap.min.js"></script>

I hope so you can solve the problem Uncaught TypeError: Cannot read property 'fn' of undefined.