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<!DOCTYPE html>
<body>
<script>
// This page runs inside a container iframe. It creates a child iframe, sets up
// a beforeunload handler that tries to navigate this page (the parent), then
// navigates the child. It reports results back via postMessage.
//
// If the browser blocks the parent navigation, the child loads successfully
// and we report parentNavigationBlocked: true.
// If the browser allows the parent navigation, this page navigates away,
// but a beforeunload handler reports parentNavigationBlocked: false first.
let triedToNavigateParent = false;
function sendResult(parentNavigationBlocked) {
window.parent.postMessage({
type: "navigation-during-beforeunload-result",
status: "complete",
triedToNavigateParent: triedToNavigateParent,
parentNavigationBlocked: parentNavigationBlocked
}, "*");
}
// If *this* page gets navigated away, report failure to the test harness.
window.addEventListener("beforeunload", () => {
if (triedToNavigateParent)
sendResult(false);
});
const frame = document.createElement("iframe");
document.body.appendChild(frame);
// Wait for the child iframe to load about:blank, then set up the test.
setTimeout(() => {
frame.contentWindow.addEventListener("beforeunload", () => {
triedToNavigateParent = true;
window.location.href = "navigation-target.html";
});
frame.addEventListener("load", () => {
// Child loaded successfully - parent navigation was blocked.
sendResult(true);
}, { once: true });
frame.contentWindow.location.href = "navigation-target.html";
}, 0);
</script>
</body>