Edit in JSFiddle 

<body>
    <script>hljs.initHighlightingOnLoad();</script>
    <pre>
        <code>
            &lt;!doctype html&gt;
            &lt;html&gt;
                &lt;body&gt;
                    Hello QNimate!!!
                &lt;/body&gt;
            &lt;/html&gt;
        </code>
    </pre>
</body>

External resources loaded into this fiddle: