gistfile1.js

            var Menu = Backbone.Model.extend({
                dimOld: function() {
                    var id = this.previous('current');
                    $('#'+id).removeClass('selected');
                },
                lightNew: function(current) {
                    $('#'+current).addClass('selected');
                }
            });
            
            // initialize instances + properties
            var menu = new Menu;
            
            menu.set({current: ""});
            
            // Bind event when user clicks on a menu item
            menu.bind("change:current", function(obj) {
                menu.dimOld();
                menu.lightNew(obj.get('current'));
            });
            
            var menu_arr = ($('#sidebar li'));
            
            $.each(menu_arr, function(i, val) {
                (function() {
                    $(menu_arr[i]).click(function() {
                        var this_id = $(menu_arr[i]).attr("id");
                        $('div#v_'+menu.previous('current')).fadeOut();
                        
                        menu.set({current: this_id});
                        $('div#v_'+this_id).delay(900).fadeIn(); 
                    })
                })(menu_arr[i])
            });