self-restarting functions:</p>
<ul>
<li><strong>runSetTimeout</strong> uses setTimeout(fn, 0) for queueing itself</li>
<li><strong>runMutation</strong> uses a MutationObserver for queueing itself</li>
</ul>

<p>
After starting the test, move your mouse so that it is hovering over the top line of output.
<p>

<p>
If the browser is behaving, you should see runSetTimeout calls interleaved with runMutation calls (either 2:1 or 1:1, depending).
</p>

<p>
On IE10, if our MutationObserver polyfill uses setImmediat