<!DOCTYPE html>
<link rel=author href="mailto:jarhar@chromium.org">
<link rel=help href="https://github.com/whatwg/html/issues/9957">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<body>
<script>
class MyElement extends HTMLElement {
  constructor() {
    super();
    this.numConnectedCallback = 0;
    this.numDisconnectedCallback = 0;
    this.attributeChangedCalls = [];
  }

  connectedCallback() {
    this.numConnectedCallback++;
  }

  disconn