Iframe checker tools,
compared.

The five options

1. DevTools Elements panel

Open DevTools, switch to Elements, search (Ctrl/Cmd + F) for iframe. The tree shows every iframe in the DOM. Hovering one highlights the element on the page; right-click for additional actions.

Good at: understanding the structural relationship between iframes and their parents, jumping straight to a frame to inspect attributes. Bad at: giving you a flat list, classifying origins, telling you which frames are hidden or which are trackers, exporting anything.

2. DevTools Console snippets

The one-liner everyone knows:

document.querySelectorAll('iframe')

And the enriched version that returns size, origin, visibility:

Array.from(document.querySelectorAll('iframe')).map(f => ({
  src: f.src || '(blank)',
  size: `${f.offsetWidth}x${f.offsetHeight}`,
  visible: f.offsetParent !== null && f.offsetWidth > 0,
  sandbox: f.getAttribute('sandbox'),
}));

Good at: precision, scripting, transferring to your own automation. Bad at: the friction of pasting on every new site, plus you have to maintain the snippets yourself. See the dedicated how-to guide for more recipes.

3. Iframe Detector (our extension)

The reason this page exists. One click on the toolbar icon and the popup shows every iframe on the active tab — sources, sizes, visibility flags, sandbox attributes, same/cross/ad/tracker classification, in-page highlight overlay, export to JSON / CSV / Markdown. Watches the DOM with a MutationObserver so frames added after page load are included.

Good at: being one click. The lowest friction option for repeated audits. Bad at:automation (it's a UI tool — for scripted pipelines you want the console approach below).

4. Wappalyzer, Ghostery, Privacy Badger

These are different products solving adjacent problems. Wappalyzer tells you what technology stack a page uses (React, GTM, Stripe, HubSpot). Ghostery and Privacy Badger detect and block third-party trackers. Neither gives you a flat list of every iframe on the page with sizes and visibility.

Good at: their actual job. Bad at: iframe-specific auditing, because that is not what they do.

5. Custom MutationObserver script

If you are building an audit pipeline that runs against many pages programmatically — for example, a continuous integration step that flags new tracker iframes on your marketing site — you write your own observer. The skeleton:

const seen = new Set();
const record = f => seen.add({ src: f.src, size: `${f.offsetWidth}x${f.offsetHeight}` });

document.querySelectorAll('iframe').forEach(record);

new MutationObserver(records => {
  for (const r of records) {
    for (const n of r.addedNodes) {
      if (!(n instanceof HTMLElement)) continue;
      if (n.tagName === 'IFRAME') record(n);
      n.querySelectorAll?.('iframe').forEach(record);
    }
  }
}).observe(document.body, { childList: true, subtree: true });

Good at: automation, integration into CI, custom logic. Bad at: day-to-day human use — too much friction to wire up just to poke at a single page.

Side-by-side comparison

Which to pick

1. You are debugging one specific frame right now. Open DevTools, find it in Elements, read its attributes. Done.
2. You need a flat list and an export. Iframe Detector for a UI; console snippet for a script.
3. You audit the same set of sites every week. Iframe Detector — the friction savings dominate.
4. You are building automated reporting against many pages. Custom MutationObserver script driven by Playwright or Puppeteer.
5. You actually want to block trackers, not just see them. Ghostery, Privacy Badger, or uBlock Origin. Iframe Detector inspects; it does not block.

Frequently asked questions