JavaScript is built-in to your browser and shouldn’t be an issue, unless it’s turn it off. I was grasping at straws trying to find out why my beautify html page wasn’t executing the script, so I test it by inserting a simple JS button:

<p id="demo">JavaScript running in Browser?</p>
<button type="button"
onclick="document.getElementById('demo').innerHTML 
= 'Hello JavaScript!'"> 
Click Me!</button>

It turned out that my problems with the external script called from the html code were path related. I found out the hard way that js/  is not the same as /js/ 

This will find the js folder:

<script type="text/javascript" src="js/jquery.min.js"></script>

This won’t:

<script type=”text/javascript” src=”/js/jquery.min.js”></script>