chromium/src/third_party/blink/web_tests/external/wpt/html/interaction/focus/the-autofocus-attribute/resources/child-autofocus.html - manifest_repos/chromium_src - Git at Google

 <!DOCTYPE html>
 <input id="target" value="This should be unfocused!" autofocus></input>

 <script>
   let got_focus = false;
   document.getElementById("target").addEventListener("focus", () => {
     got_focus = true;
   });

   window.addEventListener("load", () => {
     parent.postMessage("child_loaded", "*");
   });

   window.addEventListener("message", event => {
     if (event.data == "report_focus_state") {
       let msg = got_focus ? "child_is_focused" : "child_is_not_focused";
       parent.postMessage(msg, "*");
     }
   });
 </script>
	<!DOCTYPE html>
	<input id="target" value="This should be unfocused!" autofocus></input>

	<script>
	let got_focus = false;
	document.getElementById("target").addEventListener("focus", () => {
	got_focus = true;
	});

	window.addEventListener("load", () => {
	parent.postMessage("child_loaded", "*");
	});

	window.addEventListener("message", event => {
	if (event.data == "report_focus_state") {
	let msg = got_focus ? "child_is_focused" : "child_is_not_focused";
	parent.postMessage(msg, "*");
	}
	});
	</script>