<html>
  <head>
    <script>
    onpageshow = function(pageShowEvent) {
      var bc = new BroadcastChannel("beforeunload_and_bfcache");
      bc.onmessage = function(event) {
        if (event.data == "nextpage") {
          bc.close();
          location.href += "?nextpage";
        } else if (event.data == "back") {
          bc.close();
          history.back();
        } else if (event.data == "forward") {
          onbeforeunload = function() {
            bc.postMessage("beforeunload");
            bc.close();
          }
          history.forward();
        } else if (event.data == "close") {
          bc.postMessage("closed");
          bc.close();
          window.close();
        }
      };
      bc.postMessage({type: pageShowEvent.type, persisted: pageShowEvent.persisted});
    };
    </script>
  </head>
  <body>
  </body>
</html>
