title: Change value of a form field based on another input
body: <p>I'll start with the code:</p>
  
  <pre><code>&lt;input type="text" name="13939069" alt="2171"&gt;
  &lt;input type="text" name="2171"&gt;
  </code></pre>
  
  <p>Basically the name is the category ID, and when there is an alt value present, it is the id of the parent category.</p>
  
  <p>What needs to happen is when the value of the parent category is changed the value of the child categories are also changed. </p>