Selecting Elements with more than one Class in jQuery
<p>I have some message elements like this...</p>

<pre><code>&lt;span class="error message"&gt;Whoops!  Don't forget your name.&lt;/span&gt;
</code></pre>

<p>And...</p>

<pre><code>&lt;span class="success message"&gt;All done!  Thank you very much.&lt;/span&gt;
</code></pre>

<p>You'll notice that two classes are being applied to a single <code>span</code> element.  This is valid markup.  How can I select elements with two classes like this?</p>

<p>Note:  I don't want all elements that have a class attribute containing "message".  I need the elements that have both "error" and "message" (and nothing else).</p>
