html/browsers/windows/post-message/resources/third-party-to-first-party-different-partition-same-origin-window.html - external/w3c/web-platform-tests - Git at Google

 <!doctype html>
 <meta charset=utf-8>
 <body>
 <script>
 // Step 3
 window.opener.postMessage("Site 2 Window", window.opener.origin);
 </script>
 </body>
	<!doctype html>
	<meta charset=utf-8>
	<body>
	<script>
	// Step 3
	window.opener.postMessage("Site 2 Window", window.opener.origin);
	</script>
	</body>