Uncaught ReferenceError: u is not defined 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: reference error $ is not defined jquery

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Example 3: register:48 Uncaught ReferenceError: $ is not defined

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Example 4: Uncaught ReferenceError: $ is not defined

You should put the references to the jquery scripts first.
<script src="jquery-3.5.1.js"></script>
<script type="text/javascript" src="script.js"></script>

Example 5: corona.html:61 Uncaught ReferenceError: $ is not defined

<script language="JavaScript" type="text/javascript" src="/js/jquery-1.2.6.min.js"></script>
<script language="JavaScript" type="text/javascript" src="/js/jquery-ui-personalized-1.5.2.packed.js"></script>
<script language="JavaScript" type="text/javascript" src="/js/sprinkle.js"></script>