<!doctype html>
<title>register, unregister, and report result to opener</title>
<body>
<script>
'use strict';

navigator.serviceWorker.register('empty-worker.js', {scope: 'scope-register'})
  .then(
    registration => {
        registration.unregister().then(() => {
            window.opener.postMessage('OK', '*');
          });
      },
    error => {
        window.opener.postMessage('FAIL: ' + error.name, '*');
      })
  .catch(error => {
      window.opener.postMessage('ERROR: ' + error.name, '*');
    });
</script>
</body>