JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>

<!-- This loads correctly as HTTPS content -->
<script type="text/javascript" src="//code.jquery.com/jquery-3.3.1.min.js"></script>

<!-- This is blocked by the browser as Mixed Active Content -->
<script type="text/javascript" src="//highcharts.com/highslide/highslide-full.min.js"></script>

<!-- Explicitly setting `https` does not change the result -- it still says this is `http` content -->
<script type="text/javascript" src="https://highcharts.com/highslide/highslide-full.min.js"></script>

</head>
<body>
<p>Lorem ipsum</p>
</body>
</html>