chromium/src/third_party/blink/web_tests/fast/loader/resources/early-load-cancel-inner.html

<a id="test" onmousedown="test()">click here</a>
<div id="outer">
</div>
<script>
function test()
{
    document.getElementById("outer").innerHTML = "<iframe src='other.html'></iframe>";
    document.getElementById("outer").innerHTML = "PASSED";
}

if (window.eventSender) {
    eventSender.mouseMoveTo(20, 20);
    eventSender.mouseDown();
}

</script>