demo · v147

Opt-in Header Check

Type a URL and click Probe. We HEAD the URL and look for Supports-Loading-Mode: prerender-cross-origin-frames.

the header

HTTP/1.1 200 OK
Content-Type: text/html
Supports-Loading-Mode: prerender-cross-origin-frames

see also

Prerendering cross-origin iframes — feature index
ChromeStatus entry

implementation reference

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