gistfile1.js

// Load JS from external source
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js" type="text/javascript"></script>

// Add inline JS
<script type="text/javascript">
	$('#message').append("Message generated on " + Date.now());
</script>

// Loads Handlebars library since the message content is using Handlebars templates
<script src="//cdnjs.cloudflare.com/ajax/libs/handlebars.js/2.0.0-alpha.1/handlebars.min.js" type="text/javascript"></script>

// Compiling Handlebars templates
<script type="text/javascript">
	var message = $("#message").html();
	var template = Handlebars.compile(message);
</script>

// Loads CSS from external source
<link rel="stylesheet" src="//cdnjs.cloudflare.com/ajax/libs/bootstrap/4.0.6/bootstrap.min.css" type="text/css">

// Add inline css
<style>
p {
	color: #222;
}
em {
	color: #000;
}
</style>