Feature Policy: lazyload

Category: Performance
Type: New or changed feature
Status: Removed (Chrome 76)
Intent stage: Removed

Breaking change: No
Enterprise impact: None
Spec maturity: Incubation
Web Platform Tests: No

WPT details: There are currently several WPT associated with "lazyload" policy which will be removed along with the feature.

Summary

The lazyload feature policy allows developers to selectively control the lazyload attribute on <iframe> and <img> using the Feature-Policy header or the <iframe> "allow" attribute. This provides more control over loading delay for embedded contents and images on a per origin basis. Use this policy to force loading to delayed or non-delayed for your entire website and all or parts of any embedded contents. Use of this policy benefits page load times.

Motivation

The policy will be removed in favor of a newer feature policy for loading, namely loading-frame-default-eager which is more aligned with how the "loading" attribute will be used.

Standards & signals

Specification: https://github.com/w3c/webappsec-feature-policy/blob/master/policies/lazyload.md
Firefox: No signal
Safari: No signal
Web developers: Positive
Tracking bug: https://crbug.com/869492

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=feature-policy-lazyload
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+Feature%20Policy%3A%20lazyload
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=Feature%20Policy%3A%20lazyload
Baseline status: https://webstatus.dev/?q=Feature%20Policy%3A%20lazyload

Docs: https://github.com/w3c/webappsec-feature-policy/issues/193

View on chromestatus.com