add vue.js cdn to your aopo code example
Example 1: vue js cdn
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.js"></script>
Example 2: vuejs cdn
/*for development ===>*/ <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
/*for production ===>*/ <script src="https://cdn.jsdelivr.net/npm/[email protected]"></script>