骨干路由器：初始化

Question

我已经看到每次回到主页时都会调用我的路由器初始化函数，而不是在应用程序启动时调用。为什么呢？

var AppRouter = Backbone.Router.extend({

    routes: {
        "": "home",
        "user/:id":"userDetails",
    },

    initialize: function(){
        this.update_my_activity();
    },

    home: function() {
        if (Parse.User.current()) {
            console.log("loggato");

            var user=new Person();
            user.savePosition();

            new BarraScreamView();
            new MenuView();
            var self=this;

            console.log("inrouterhome");
            Models.utenti = new Usercollection();
            Models.utenti.fetch({
                success: function(object) {
                    console.log(object);
                    var page=new Homelistuser({model:object});
                    self.changePage(page);
                },

                error: function(amici, error) {
                }
            });

        } else
            new LoginView();
    }




       changePage: function (page) {
   this.update_my_activity(); 
   $('#pagina').empty();


    page.render();
    $('#pagina').append($(page.el));
  },