举例说明Javascript如何实现面向对象？

类：
function DelegateObject(){
var obj = new Object();

类：
function DelegateObject(){
var obj = new Object();
obj.value = “”;
obj.FormatString = null;
obj.toString = function _toString(){
if(obj.FormatString != null)
return this.FormatString(this.Value);
else
return this.Value;
}
return obj;
}
var obj = new DelegateObject();

委托：
function DelegateObject(){
var obj = new Object();
obj.value = “”;
obj.FormatString = null;
obj.toString = function _toString(){
if(obj.FormatString != null)
return this.FormatString(this.Value);
else
return this.Value;
}
return obj;
}

function ConvertToString(value){
return “Result:” + value;
}
var obj = new DelegateObject();
obj.Value = “Hello World!”;
obj.FormatString = ConvertToString;
document.write(obj.toString());

重写：
function DelegateObject(){
var obj = new Object();
obj.toString = function _toString(){
if(obj.FormatString != null)
return this.FormatString(this.Value);
else
return this.Value;
}
return obj;
}

继承：
function DelegateObject(){
var obj = new Object();
obj.value = “”;
obj.FormatString = null;
obj.toString = function _toString(){
if(obj.FormatString != null)
return this.FormatString(this.Value);
else
return this.Value;
}
return obj;
}

function Class2(){
var obj = new DelegateObject();
return obj;
}

function ConvertTOString(value){
return “Result:” + value;
}

var obj = new Class2();
obj.Value = “Hello World!”;
obj.FormatString = ConvertTOString;
document.write(obj.toString());

事件：
function EventHandler(){
var eventobj = new Object();
eventobj._eventHandler = null;
eventobj.Activate = function _activate(){
if(eventobj._eventHandler != null)
eventobj._eventHandler();
}
eventobj.Add = function _add(eventHandler){
eventobj._eventHandler = EventHandler;
}
eventobj.Remove = function _remove(){
eventobj._eventHandler = null;
}
return eventobj;
}

function mouseClick(){
alert(“Hello World!”);
}

var obj = new EventHandler();
obj.Add(mouseClick());
obj.Activate();

枚举：
function _StatusList(){
var object = new Object();
object.正常= “Normal”;
object.删除= “Delete”;
object.审核通过= “Auditing”;
object.驳回 = “OverRule”;
return object;
}
Object.prototype.StatusList = new _StatusList();
function TObject(){
var obj = new Object();
obj.Type = “YiZhu”;
obj.Status = Object.StatusList.审核通过;
}
alert(obj.Status);