Get all elements inside iframe tag
<blockquote>
  <p>this is my part of code now i'm using iframe tag and loaded epub on iframe tag
  then i don't know how to get all elements inside iframe tag.</p>
</blockquote>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>jQuery(document).ready(function($) {
  var tmp = $('#epub_loader iframe').contents().find('body').html();
  alert(tmp);
});</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;iframe id="epub_loader" href="test.epub" &gt;&lt;/iframe&gt;</code></pre>
</div>
</div>
</p>

<p>`</p>