title: Add class to td with colspan=2
body: <p>I want to add a Class to every td which has <code>colspan=2</code>:</p>
  
  <pre><code>&lt;div class="content"&gt;
      &lt;table&gt;
          &lt;tr&gt;
              &lt;td&gt;zuppa di zucchini&lt;/td&gt;
              &lt;td&gt;€ 6,00&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td colspan="2"&gt;huisgemaakte soep van courgette met munt&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;insalata caprese&lt;/td&gt;
              &lt;td&gt;€ 6,00&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td colspan="2"&gt;frisse salade met tomaatjes,
                              mozzarella en verse pesto&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/table&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I thought something like this would do the trick, but it doesn't work:</p>
  
  <pre><code>$('.content td[colspan=2]').addClass('dus');
  </code></pre>
  
  <p>Can somebody please help me? Thanks in advance!</p>