How to count all elements where custom attribute has a certain value?
<p>How can I determine the total amount of <code>div</code>'s in this <code>td</code> where <code>data-something</code> is "yes"?</p>

<pre><code>&lt;td id='tableData'&gt;
  &lt;div class="test" data-something="yes"&gt;&lt;/div&gt;
  &lt;div class="test" data-something="no"&gt;&lt;/div&gt;
  &lt;div class="test" data-something="yes"&gt;&lt;/div&gt;
&lt;/td&gt;
</code></pre>
