675621-1.html
<!DOCTYPE html>
<body>
<script>
document.addEventListener("DOMSubtreeModified", function() {}, false);
document.body.insertAdjacentHTML("afterbegin", "<p>foo");
</script>
<!DOCTYPE html>
<body>
<script>
document.addEventListener("DOMSubtreeModified", function() {}, false);
document.body.insertAdjacentHTML("afterbegin", "<p>foo");
</script>