Read SRC from iframe

This fiddle attempts to read the SRC of an iframe, after it changes internally.

by David Iglesias

HTML

<iframe id="watch-me" src="https://dit-embedded-iframe-test.firebaseapp.com/index.html"></iframe>

<div>
  <button id="read-src">Get iframe.src</button>
  <ul>
    <li>iframe.src: <span id="iframe-src">n/a</span></li>
    <li>contentDocument.URL: <span id="iframe-url">n/a</span></li>
  </ul>
</div>

CSS

body {
  background-color: #bbf;
}

JavaScript

let refresh = document.getElementById('read-src');
let iframe = document.getElementById('watch-me');
let output = document.getElementById('iframe-src');
let output2 = document.getElementById('iframe-url');

refresh.addEventListener('click', (event) => {
  let contentDoc = iframe.contentDocument;
  output.innerText = iframe.src;
  output2.innerText = contentDoc != null ? contentDoc.URL : 'inaccessible';
});