title: How to check if content exists in iframe with external source
body: <pre><code>&lt;div class="cont"&gt;
      &lt;iframe id="iframe" sandbox="" src="external_website" width="100%" height="100%" frameborder="0"&gt;&lt;/iframe&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to detect with JQuery whether i got content from other website in my iframe or not?</p>
  
  <p>I have tried different things, nothing helped.
  Thanks.</p>