我的代码，生成一条订单，再生成一条通知，js 获取，然后提示，但是居然提示了 7 次。不知道哪里出现问题，以下是我的代码：

$(document).on('page:change',  function() { 
  NProgress.done();

  MessageBus.start(); // call once at startup
  // how often do you want the callback to fire in ms
  MessageBus.callbackInterval = 500;
  MessageBus.subscribe("/notifications_count/" + App.access_token, function(data){
    // data shipped from server

    var div, link, new_title, span, url;
    span = $(".notification-count span");
    link = $(".notification-count a");
    new_title = document.title.replace(/^\(\d+\) /, '');
    if (data.count > 0) {
      span.show();
      new_title = "(" + data.count + ") " + new_title;

      link.addClass("new");

      $.notify({
        title: "<strong>" + data.title + "</strong> ",
        message: "您有新订单(" + data.content + ")，请赶快处理 <a href=\"" + data.content_path + "\">点击这里</a>"
      },{
        delay: 10000
      });
    } else {
      span.hide();
      link.removeClass("new");
    }
    span.text(data.count);
    return document.title = new_title;
  });
});