 <p>I am not sure whether I understand your question correctly or not.</p> <p>We can get the iframe document by calling</p> <p><code>iframeEl.contentWindow.document</code></p> <p>Then we can control the html, css inside it.</p> <p>Be careful about the same origin policy:</p> <p>We can only control the iframe the same origin as the main page. </p>