Disqus supports automatic syntax highlighting in a number of languages. To use this feature, place your code inside <pre><code> tags. For example:

<pre><code>
 var foo = 'bar';
 alert('foo');
 </code></pre>

By default, Disqus will try to automatically detect the language. It's pretty good at this, but you can give it a hand by doing the following:

<pre><code class="javascript">
 var foo = 'bar';
 alert('foo');
 </code></pre>

Note: Syntax highlighting will automatically close tags. To place a tag in code without closing, use &#60; and &#62; instead of < and >, to override this behavior.