title: Google AMP html - insert amp-iframe without src attribute
body: <p>I'm trying to run a script inside an AMP page.</p>
  
  <p>There is no page I need to load within the <code>src</code> attribute; my script should inject an <code>&lt;iframe&gt;</code> with the correct <code>src</code> (it is unknown at first load, only received in response to a request made by my script).</p>
  
  <p>Is this possible in AMP?</p>
  
  <p>Disclaimer: I'm open to different approaches to accomplish the same result - injecting an <code>&lt;iframe&gt;</code> with an <code>src</code> attribute within an AMP page.</p>
  
  <p>Thank you</p>