firebase.database is not a function

JavaScript
<script src="https://www.gstatic.com/firebasejs/7.24.0/firebase-auth.js"></script>
<script src="https://www.gstatic.com/firebasejs/7.24.0/firebase-database.js"></script>
// don't forget to change the "7.24.0" part of the url with the current version <script src="https://www.gstatic.com/firebasejs/3.1.0/firebase-auth.js"></script>
<script src="https://www.gstatic.com/firebasejs/3.1.0/firebase-database.js"></script>
Source

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