title: Capture iframe window response and send to parent window
body: <p>I have a html page with an iframe like this </p>
  
  <pre><code>&lt;html&gt;
   &lt;body&gt;
      &lt;iframe height="300px" width="100%" src="https://......."&gt;
     &lt;/iframe&gt;
   &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>This works and I see the page mentioned in <code>src</code> attribute of iframe. This page is basically a third party login page. I can provide a callback url to the third party login url which is called on successfull login. </p>
  
  <p>This callback url is my backend endpoint which is getting called. From my backend I return a new url. Now I want my whole window(not just the iframe) to be redirected to this url returned from my backend system.  </p>
  
  <p>I am not sure how to catch the value returned from my backend system.</p>
  
  <p>I have read articles on how to pass value from iframe to parent window. I am thinking of passing the url to the parent window and load that using <code>window.location.href</code>. </p>
  
  <p>I am stuck on how to capture the value returned from my backend system.<br>
  Any help is much appreciated.</p>