ck on the inner box:</p>
<div class="outer">
  <div class="inner"></div>
</div>

<script>

// Based on: https://jakearchibald.com/2015/tasks-microtasks-queues-and-schedules/

log_test(function(t, log) {
    // Let's get hold of those elements
    var outer = document.querySelector('.outer');
    var inner = document.querySelector('.inner');

    // Let's listen for attribute changes on the
    // outer element
    new MutationObserver(function() {
        log('mutate');
    }).observe(outer, {
        attri