Answers for "index2.html:21 Uncaught ReferenceError: $ is not defined"

index.html?profile=Responsive:30 Uncaught ReferenceError: $ is not defined

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>

Uncaught ReferenceError: $ is not defined

jQuery must be loaded first before your script. 

example:
<script src="path/to/jquery.js"></script> <!-- or using CDN is up to you  -->
<script type="text/javascript">
	// your script here...
</script>