eferenceError: $ is not defined at (index):13 code example
Example 1: Uncaught ReferenceError: $ is not defined
<script src="https://code.jquery.com/jquery-1.9.1.js"></script>
<script src="path-para-seu-script"></script>
Example 2: $ is not defined
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>