title: Check if select options is selected
body: <p>I am running dataTables plugin for a project.</p>
  
  <p>Could you please show me where I am doing it wrong (it is extremely simple and it doesn't show any errors):</p>
  
  <pre><code>&lt;select name="DataTables_Table_0_length" aria-controls="DataTables_Table_0" class="form-control input-sm"&gt;
      &lt;option value="10"&gt;10&lt;/option&gt;
      &lt;option value="25"&gt;25&lt;/option&gt;
      &lt;option value="50"&gt;50&lt;/option&gt;
      &lt;option value="100"&gt;100&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>Basically that is what I have generated. So I want to select the 50 and 100 values to all the tables on the page and show the footer of the generated tables only when these two results are selected.</p>
  
  <p>I tried the following (just for value="50"):</p>
  
  <pre><code>var selected_result = $('select option:nth(2)');
  var tfoot = $('tfoot');
  tfoot.hide();
  
  if (selected_result.is(':selected')) { tfoot.show(); }
  </code></pre>
  
  <p>Thank you</p>