<!doctype html> <meta charset="utf-8"> <title>activeElement when focusing same-site iframe's contentWindow</title> <script> let log = ""; function getLog() { return log; } window.onmessage = function(e) { log += e.data; }; window.onload = function() { log += "outeronload,"; log += "activeElement:" + document.activeElement.tagName + ","; log += "willfocusiframe,"; document.getElementsByTagName("iframe")[0].contentWindow.focus(); log += "didfocusiframe,"; log += "activeElement:" + document.activeElement.tagName + ","; log += "willbluriframe,"; document.getElementsByTagName("iframe")[0].contentWindow.blur(); log += "didbluriframe,"; log += "activeElement:" + document.activeElement.tagName + ","; log += "willspineventloop," opener.step_timeout(function() { opener.postMessage(getLog(), "*"); }, 1500); } </script> <iframe src="activeelement-after-focusing-same-site-iframe-inner-contentwindow.html"></iframe>