title: Django Admin intercept onchange event of a field and make an action
body: <p>In my django project i would clear a field value every time another select field have an onChange event.
  I have an add form like thisone:</p>
  
  <p><a href="https://i.stack.imgur.com/8oqox.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8oqox.png" alt="enter image description here"></a></p>
  
  <p>every time Template field change (onChange), Test Case field have to become blank.</p>
  
  <p>How can i do this in a django admin add or edit page?</p>
  
  <p>So many thanks in advance</p>