title: Add element to another child if parent does not contain
body: <p>How can I check each <code>div.item</code> to see if it does <strong>not</strong> contain <code>span.premium</code> and then add a new span (let's call that <code>span.free</code>) to <code>div.screenshot</code>? </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
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  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="video1" class="item"&gt;
    &lt;div class="screenshot"&gt;
      &lt;img src="image1.png" /&gt;
    &lt;/div&gt;
    &lt;h3&gt;I am Video 1&lt;/h3&gt;
  &lt;/div&gt;
  &lt;div id="video2" class="item"&gt;
    &lt;div class="screenshot"&gt;
      &lt;img src="image2.png" /&gt;
    &lt;/div&gt;
    &lt;h3&gt;I am Video 2 &lt;span class="premium"&gt;P&lt;/span&gt;&lt;/h3&gt;
  &lt;/div&gt;
  &lt;div id="video3" class="item"&gt;
    &lt;div class="screenshot"&gt;
      &lt;img src="image3.png" /&gt;
    &lt;/div&gt;
    &lt;h3&gt;I am Video 3&lt;/h3&gt;
  &lt;/div&gt;</code></pre>
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  </div>
  </p>