<!DOCTYPE html>
<title>Service Worker: frame for getRegistrations()</title>
<script>
var scope = 'scope-for-getregistrations';
var script = 'empty-worker.js';
var registration;

navigator.serviceWorker.register(script, { scope: scope })
  .then(function(r) { registration = r; window.parent.postMessage('ready', '*'); })

self.onmessage = function(e) {
  if (e.data == 'unregister') {
    registration.unregister()
      .then(function() {
          e.ports[0].postMessage('unregistered');
        });
  }
};
</script>