<script>
onpageshow = function(e) {
  var bc2 = new BroadcastChannel("testUrl2_bfcache");
  bc2.onmessage = function(event) {
    if (event.data == "back") {
      bc2.close();
      history.back();
    }
  };
  bc2.postMessage({type: e.type, persisted: e.persisted});
};
</script>
