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Author: nyaxt

README.md

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+# LazyEmbeds: Explainer
+
+## Authors
+* [@nyaxt](https://github.com/nyaxt)
+
+## Participate
+* [github.com/nyaxt/lazyembeds/issues](https://github.com/nyaxt/lazyembeds/issues)
+
+## Introduction
+
+We (Google Chrome team) are currently exploring if perceived page load speed can be improved by introducing a different loading schedule to third-party embeds, such as social media, videos, analytics, live chat.
+
+Here, we draw attention to cross-origin <iframe>s, which is widely used to integrate a website with such 3rd party SaaS.
+
+## Goals
+User agent explores different loading schedules for cross-origin <iframe>s. This is done by inserting arbitrary delays before cross-origin iframe to start.
+
+We aim to selectively apply the delay using heuristics gathered from signals such as:
+- Whether <iframe> is in the viewport or not
+- Size of the iframe
+- The origin of the iframe
+- etc.
+
+## Non-goals
+We currently do not plan to apply the delay to same-origin iframes.
+
+## The monkey patch to HTML spec
+The [*will lazy load element steps*](https://html.spec.whatwg.org/#will-lazy-load-element-steps) is modified to take `request` as an additional parameter. Also, we insert the following steps before step 3:
+
+3. If _element_’s lazy loading attribute is set and is in the Eager state, then return false.
+
+4. If _element_’s document’s URL is not same origin with [_request_](https://fetch.spec.whatwg.org/#concept-request)’s URL’s origin, optionally, the user agent may choose to return true, if it believes doing so would improve the loading experience.