Setting select index
<p>I know I can select an option in a select box by doing </p>

<pre><code>$('#selectBox :nth-child(4)').attr('selected', 'selected');
</code></pre>

<p>But how can I do this through a returned jQuery object? e.g. something like</p>

<pre><code>var box = $('#selectBox');
$(box  :nth-child(4)').attr('selected', 'selected');
</code></pre>
