is not defined at script.js:2 code example
Example: Uncaught ReferenceError: $ is not defined
<script src="https://code.jquery.com/jquery-1.9.1.js"></script>
<script src="path-para-seu-script"></script>
<script src="https://code.jquery.com/jquery-1.9.1.js"></script>
<script src="path-para-seu-script"></script>