title: Selecting half the elements with :nth-child?
body: <p>Take the following code for instance:</p>
  
  <pre><code>&lt;ul&gt;
    &lt;li&gt;Hello World&lt;/li&gt;
    &lt;li&gt;Hello World&lt;/li&gt;
    &lt;li&gt;Hello World&lt;/li&gt;
    &lt;li&gt;Hello World&lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>Is it possible, using <code>:nth-child()</code> or otherwise, to select exactly <strong>half</strong> of the total elements? The code should select the first/last <em>two</em> <code>li</code>s in the above instance, then if I were to increase the number of <code>li</code>s to six, it would select the first/last <em>three</em>.</p>
  
  <p>I feel I'm going to have to use JavaScript...</p>