<!DOCTYPE html>
<!--
  Issue 1336672
  This is a cross-origin iframe for https://codepen.io/mustaqahmed/pen/ZEKvPBb
-->
<h2>Cross-origin subframe</h2>
<div><input id="button" type="button" value="Click here once" /></div>
<script>
  document.getElementById("button").onclick =
    () => window.top.location="https://www.example.com";
</script>

Add a subframe doing top-frame nav.
Add a subframe doing top-frame nav.
