title: window.frames returns only the base window
body: <p>I'm trying to access the <code>window</code> object of an iframe inserted. When I check <code>window.frames</code> in the inspection, it is the base window's window object not the one of the iframe and <code>window.frames.length</code> is 1. How do I access window object of iframes?</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
    &lt;head&gt;
      &lt;title&gt;Hello!&lt;/title&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;meta http-equiv="X-UA-Compatible" content="IE=edge"&gt;
      &lt;meta name="viewport" content="width=device-width, initial-scale=1"&gt;
      &lt;link rel="stylesheet" href="style.css"&gt;
      &lt;script src="script.js" defer&gt;&lt;/script&gt;
    &lt;/head&gt;  
    &lt;body&gt;
        some contents
        &lt;iframe src="iframe.html"&gt;&lt;/iframe&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  
  </code></pre>