jQuery :first and :last selector
<pre><code>$('div#nutrition-fact-content table tr:first td:first').addClass('product-volume');
$('div#nutrition-fact-content table tr:first td:last').addClass('flavor-name');
</code></pre>

<p>In the above code, the second line of jQuery applies the class. The td before it never receives the class. I also tried just tr:first to class the row, and that doesn't get a class either. Why not?</p>
