uncaught referenceerror is not defined at anonymous code example

Example 1: $ is not defined

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>

Example 2: register:48 Uncaught ReferenceError: $ is not defined

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