Why it matters
Googlebot does not scroll, so a scroll event listener never fires and the content it would load never appears. Google renders with a very tall viewport instead (said at Search Central Live to be around 10,000 pixels), so content loaded when it enters the viewport does load during rendering.
How to meet it
Use loading="lazy" on img and iframe elements, with a real src plus width and height, and an IntersectionObserver for other components. Never make indexable content depend on scroll position, scroll depth or a timer. Treat the tall viewport as a safety margin, not a target, and give long lists paginated URLs (DEV-URL-07).
How to test it
The rendered HTML in URL Inspection contains below-the-fold images and list items. A code search finds no addEventListener('scroll') or onscroll handler that loads content.
How Regensbot covers it
Decided automatically once Regensbot renders your pages.
Headless Chromium renders the page on an isolated render service, and the raw and the rendered HTML run through the same parsers.
Sources
Google documents02
- 01Fix lazy-loaded contentGoogle Search Central (opens in a new tab)
- 02March 2023 Google SEO office hoursGoogle Search Central (SEO office hours transcript, March 2023) (opens in a new tab)
Claims in the knowledge base06
- D2-C198ConfirmedLightning session D: Rendering and JavaScriptShown on screen
- D2-C197ConsistentLightning session D: Rendering and JavaScriptShown on screen
- D2-C271ConfirmedWhat is Google friendly JavaScriptSaid on stage
- D2-C274ConfirmedWhat is Google friendly JavaScriptSaid on stage
- D2-C199ConsistentLightning session D: Rendering and JavaScriptShown on screen
- D2-C272UndocumentedWhat is Google friendly JavaScriptSaid on stage
Claim IDs refer to the Search Central Live 2026 knowledge base. The knowledge base (opens in a new tab)
- Confirmed
- Google's documentation states the same thing.
- Consistent
- Google's documentation supports it without stating it.
- Undocumented
- Said or shown at the event, not in the documentation.