Lazily load below-the-fold iframes and images

Support deferring the load of below-the-fold iframes and images on the page until the user scrolls near them. This is to reduce data usage, memory usage, and speed up above-the-fold content. Web pages can also use a per-element "loading" attribute to either force or opt-out of the browser's default LazyLoad behavior.

Comments

Chrome uses heuristics to recognize and avoid deferring hidden iframes likely used for analytics or communication, as well as hidden images like tracking pixels, since deferring those could break their functionality. If the viewport is scrolled within a distance threshold of deferred content, it will start loading in. The distance depends on factors like the current network speed, such that it can be tuned so that deferred content is almost always finished loading by the time it becomes visible.

Demo

Documentation

Specification

Editor's draft

Status in Chromium

Blink>Loader


In development (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • No public signals
  • No public signals
  • Public support
  • Positive

Owners

Intent to Implement url

Intent to Implement thread

Last updated on 2019-04-10