Intent to Experiment: Prerendering cross-origin iframes
Yoichi Osato
Contact emails
Explainer
https://github.com/WICG/nav-speculation/blob/main/prerendering-cross-origin-iframes.md
Specification
https://wicg.github.io/nav-speculation/prerendering.html
Summary
Prerenders cross-origin iframes with an opt-in response header. Browsers will now prerender all cross-origin frames if the top-level frame's HTTP response includes the Supports-Loading-Mode: prerender-cross-origin-frames.
Blink component
Web Feature ID
speculation-rules
TAG review
https://github.com/w3ctag/design-reviews/issues/1207
TAG review status
Not applicable
Goals for experimentation
Gather feedback from web authors who already are interested in this feature.
Risks
Interoperability and Compatibility
The entire speculative loading feature is a progressive enhancement, so in general risks are low in this area.
Gecko: No signal (https://github.com/mozilla/standards-positions/issues/1376)
WebKit: No signal (https://github.com/WebKit/standards-positions/issues/636)
Web developers: Positive Our partners show interests in having this feature.
Other signals:
WebView application risks
(This feature is not supported in WebView.)
Ongoing technical constraints
No information provided
Debuggability
The cross-origin iframe prerendering should be debuggable as well as top frame's one: https://developer.chrome.com/docs/devtools/application/debugging-speculation-rules#prerender
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?
No
Windows, Mac, Linux, ChromeOS, Android. WebView doesn't support speculation rules prerendering because prerendering navigation breaks the lifecycle (e.g., callback sequence) of the WebView.
Is this feature fully tested by web-platform-tests?
Yes
Flag name on about://flags
"prerender2-cross-origin-iframes" from M148
Finch feature name
Prerender2CrossOriginIframes
Requires code in //chrome?
False
Estimated milestones
Origin trial desktop first 147
Origin trial desktop last 152
DevTrial on desktop 147
Origin trial Android first 147
Origin trial Android last 152
DevTrial on Android 147
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5112398709129216?gate=5126116666900480
Links to previous Intent discussions
Intent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/68b670ba.050a0220.270bc4.0593.GAE%40google.com
This intent message was generated by Chrome Platform Status.
