title: Returning a value from an iFrame in a popup to its parent window
body: <p>Okay, ridiculously simple question, but it is doing my head in so any help would be appreciated!</p>
  
  <p>I need to return a value to a form field, the value is returned in an iframe that is in a popup window.</p>
  
  <p>So, I was thinking something along the lines of</p>
  
  <pre><code>window.top.parent.form.field.value = 'new value'
  </code></pre>
  
  <p>But that just gives me an error, any ideas would be really helpful! (not the greatest person in the world with javascript me)
  Cheers</p>