Copy following in the head section
1234<link rel="stylesheet"
href="http://cdn.jsdelivr.net/gh/highlightjs/cdn-release@9.12.0/build/styles/default.min.css">
<script src="http://cdn.jsdelivr.net/gh/highlightjs/cdn-release@9.12.0/build/highlight.min.js"></script>
<script>hljs.initHighlightingOnLoad();</script>
The code that needs highlighting should be in the following form,
12345<pre class="language"><code>
...
code
...
</code></pre>