JAVASCRIPT的MVC示例

/** * The Model. Model stores items and notifies * observers about changes. */function ListModelthis._items = items;    this._selectedIndex = -1;    this.itemAdded = new Event(this);    this.itemRemoved = new Event(this);    this.selectedIndexChanged = new Event(this);}ListModel.prototype = {    getItems : function return [].concat(this._items);    },    addItem : function this._items.push(item);        this.itemAdded.notify({ item : item });    },    removeItemAt : function var item;        item = this._items[index];        this._items.splice(index, 1);        this.itemRemoved.notify({ item : item });        if (index === this._selectedIndex) {            this.setSelectedIndex(-1);        }    },    getSelectedIndex : function return this._selectedIndex;    },    setSelectedIndex : function var previousIndex;        previousIndex = this._selectedIndex;        this._selectedIndex = index;        this.selectedIndexChanged.notify({ previous : previousIndex });    }};

Event is a simple class for implementing the Observer pattern:

function Eventthis._sender = sender;    this._listeners = [];}Event.prototype = {    attach : function this._listeners.push(listener);    },    notify : function var index;        for (index = 0; index < this._listeners.length; index += 1) {            this._listeners[index](this._sender, args);        }    }};

The View class requires defining controls for interacting with. There are numerous alternatives of interface for the task, but I prefer a most simple one. I want my items to be in a Listbox control and two buttons below it: "plus" button for adding items and "minus" for removing selected item. The support for selecting an item is provided by Listbox's native functionality. A View class is tightly bound with a Controller class, which "... handles the input event from the user interface, often via a registered handler or callback" (from wikipedia.org).

Here are the View and Controller classes:

/** * The View. View presents the model and provides * the UI events. The controller is attached to these * events to handle the user interraction. */function ListViewthis._model = model;    this._elements = elements;    this.listModified = new Event(this);    this.addButtonClicked = new Event(this);    this.delButtonClicked = new Event(this);    var _this = this;    // attach model listeners    this._model.itemAdded.attach(function this.rebuildList();    });    this._model.itemRemoved.attach(function this.rebuildList();    });    // attach listeners to HTML controls    this._elements.list.change(function this.listModified.notify({ index : e.target.selectedIndex });    });    this._elements.addButton.click(function this.addButtonClicked.notify();    });    this._elements.delButton.click(function this.delButtonClicked.notify();    });}ListView.prototype = {    show : function this.rebuildList();    },    rebuildList : function var list, items, key;        list = this._elements.list;        list.html('');        items = this._model.getItems();        for (key in items) {            if (items.hasOwnProperty(key)) {                list.append($('<option>' + items[key] + '</option>'));            }        }        this._model.setSelectedIndex(-1);    }};/** * The Controller. Controller responds to user actions and * invokes changes on the model. */function ListControllerthis._model = model;    this._view = view;    var _this = this;    this._view.listModified.attach(function this.updateSelected(args.index);    });    this._view.addButtonClicked.attach(function this.addItem();    });    this._view.delButtonClicked.attach(function this.delItem();    });}ListController.prototype = {    addItem : function var item = window.prompt('Add item:', '');        if (item) {            this._model.addItem(item);        }    },    delItem : function var index;        index = this._model.getSelectedIndex();        if (index !== -1) {            this._model.removeItemAt(this._model.getSelectedIndex());        }    },    updateSelected : function this._model.setSelectedIndex(index);    }};

And of course, the Model, View, and Controller classes should be instantiated. The sample, which you can below, uses the following code to instantiate and configure the classes:

$(function var model = new ListModel(['PHP', 'JavaScript']),        view = new ListView(model, {            'list' : $('#list'),             'addButton' : $('#plusBtn'),             'delButton' : $('#minusBtn')        }),        controller = new ListController(model, view);        view.show();});?

<id="list" size="10" style="width: 15em"></<<id="plusBtn">  +  </<id="minusBtn">  -  </button>