focus/support/hasfocus-inner.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>hasFocus inner</title>
<script>
var seenFocus = false;
var seenBlur = false;
window.onmessage = function(e) {
    if (e.data == "focus") {
        let input = document.getElementsByTagName("input")[0];
        input.onblur = function() {
            seenBlur = true;
        }
        input.onfocus = function() {
            if (seenFocus) {
                if (seenBlur) {
                    window.parent.postMessage("restored", "*");
                } else {
                    window.parent.postMessage("noblur", "*");
                }
            } else {
                seenFocus = true;
                window.parent.postMessage("focused", "*");
            }
        }
        input.focus();
    } else if (e.data == "hasfocus") {
        if (document.hasFocus()) {
            window.parent.postMessage("wrongfocus", "*");
        } else {
            window.parent.postMessage("close", "*");
        }
    }
}
</script>
</head>
<body>
<input>
</body>
</html>