title: Event listener for externally loaded page
body: <p>I have included an external page using an iframe. The page is a form and will accept input. I want to capture the successful submission of the form. </p>
  
  <p>I notice that when the form was successfully submitted a div element is appended to the page (refer below): </p>
  
  <pre><code> "&lt;div class="appriseOverlay" id="aOverlay" style="height: 100%; width: 100%; display: block;"&gt;&lt;/div&gt; &lt;div class="appriseOuter" style="left: 50%; top: 200px; display: block; transform: translate(-50%, -50%);"&gt;&lt;div class="appriseInner"&gt;Data successfully submitted&lt;div class="aButtons"&gt;&lt;button value="ok"&gt;Ok&lt;/button&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;"
  </code></pre>
  
  <p>using the load seems not able to detect. I have no control over the external page. </p>
  
  <p>Thank you all in advanced.</p>