How can I wrap children elements inside a div with pure javascript? : <p>For instance, I have the following code</p>

<pre><code>&lt;div class="parent&gt;
  &lt;p&gt; Item 1 &lt;/p&gt;
  &lt;p&gt; Item 1 &lt;/p&gt;
  &lt;p&gt; Item 1 &lt;/p&gt;
&lt;/div&gt;
</code></pre>

<p>I want turn the code above into the following code with pure javascript</p>

<pre><code>&lt;div class="parent&gt;
  &lt;div class="parent-child&gt;
    &lt;p&gt; Item 1 &lt;/p&gt;
    &lt;p&gt; Item 1 &lt;/p&gt;
    &lt;p&gt; Item 1 &lt;/p&gt;
  &lt;/div&gt;
&lt;/div&gt;
</code></pre>
