MIV spike — cross-origin embed harness

This page is served from miv-cme-host.pages.dev; the widget is served from miv-cme-spike.pages.dev. Different origin, so every frame below is a genuine third-party embed — the same relationship the widget has inside Wix, minus Wix. Wix is unavailable, so this is standing in for it.

Each frame varies exactly one thing. Read each widget's own debug panel for its readings; the shared log at the bottom shows what reached this parent.

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1 · fixed parent listens

?mode=fixed — 16:9 box. Parent acks resize messages. The baseline we expect to ship. It sends ping, not resize, so the ack proves the channel while the box deliberately stays put.

waiting…

2 · auto / self-size parent listens

?mode=auto — natural height, resize protocol live, parent applies the height it is asked for. This is the "self-sizing works" case, and the only frame whose box should visibly change size.

waiting…

3 · probe parent listens

?probe=1 — the widget sends resize, the parent acks but refuses to apply it. Separates "acks arrive" from "the height was actually applied", which are different failures on Wix.

waiting…

4 · auto parent does NOT listen

?mode=auto, but this parent deliberately ignores messages from this frame and never acks. This is the plain Wix HTML embed with no Velo code. Its panel should read N sent / 0 ack → NO PARENT LISTENER. Everything else about it is identical to frame 2, so the difference is attributable.

waiting…

5 · sandboxed, Wix-like parent listens

Sandbox set to allow-scripts allow-same-origin allow-popups allow-forms allow-presentation — the permissive set an embed host typically uses. Because allow-same-origin is present the origin stays real, so this should behave like frame 2.

waiting…

6 · sandboxed, NO allow-same-origin opaque origin

Sandbox is allow-scripts only. This is the risk case: dropping allow-same-origin gives the document an opaque origin. Expect window.origin: null, storage APIs throwing, and the server seeing Origin: null — which would defeat an origin allow-list. This is our early reading on whether Wix's HTML-code mode is viable at all.

waiting…

Messages received by this parent

nothing yet…