定义类的方式

1、工厂方式

function createCar(){
	var oTempCar=new Object();
	oTempCar.color="red";
	oTempCar.doors=4;
	oTempCar.mpg=23;
	oTempCar.showColor=function(){
		alert(this.color);
	};
	return oTempCar;
}
var oCar1=createCar();
var oCar2=createCar();
oCar1.showColor();//red
oCar2.showColor();//red

function createCar(sColor,iDoors,iMpg){
	var oTempCar=new Object();
	oTempCar.color=sColor;
	oTempCar.doors=iDoors;
	oTempCar.mpg=iMpg;
	oTempCar.showColor=function(){
		alert(this.color);
	};
	return oTempCar;
}
var oCar1=createCar("red",4,25);
var oCar2=createCar("blue",4,23);
oCar1.showColor();//red
oCar2.showColor();//blue

function showColor(){
	alert(this.color);
}
function createCar(sColor,iDoors,iMpg){
	var oTempCar=new Object();
	oTempCar.color=sColor;
	oTempCar.doors=iDoors;
	oTempCar.mpg=iMpg;
	oTempCar.showColor=showColor;
	return oTempCar;
}
var oCar1=createCar("red",4,12);
var oCar2=createCar("blue",4,23);
oCar1.showColor();//red
oCar2.showColor();//blue

2、构造函数方式

function Car(sColor,iDoors,iMpg){
this.color=sColor;
this.doors=iDoors;
this.mpg=iMpg;
this.showColor=function(){
alert(this.color);
};
}
var oCar1=new Car("red",4,45);
var oCar2=new Car("blue",4,34);
oCar1.showColor();//red
oCar2.showColor();//blue

3、原型方式

function Car(){
}
Car.prototype.color="red";
Car.prototype.doors=4;
Car.prototype.mpg=23;
Car.prototype.showColor=function(){
alert(this.color);//if this replaced by Car,output undefined
};
var oCar1=new Car();
var oCar2=new Car();
oCar1.showColor();//red
oCar2.showColor();//red
alert(oCar1 instanceof Car);//true
function Car(){
}
Car.prototype.color="red";
Car.prototype.doors=4;
Car.prototype.mpg=23;
Car.prototype.drivers=new Array("Mike","Sue");
Car.prototype.showColor=function(){
alert(this.color);//if replaced by Car,output undefined
};
var oCar1=new Car();
var oCar2=new Car();
oCar1.drivers.push("vivi");
alert(oCar1.drivers);//Mike,Sue,vivi
alert(oCar2.drivers);//Mike,Sue,vivi

4、混合的构造函数原型方式

function  Car(sColor,iDoors,iMpg){
this.color=sColor;
this.doors=iDoors;
this.mpg=iMpg;
this.drivers=new Array("Minke","susan");
}
Car.prototype.showColor=function(){
alert(this.color);
};
var oCar1=new Car("red",4,45);
var oCar2=new Car("blue",4,12);
oCar1.showColor();//red
oCar2.showColor();//blue
oCar1.drivers.push("mingming");
alert(oCar1.drivers);//Minke,susan,mingming
alert(oCar2.drivers);//Minke,susan

5、动态原型方法

function Car(sColor,iDoors,iMpg){
	this.color=sColor;
	this.doors=iDoors;
	this.mpg=iMpg;
	if(typeof Car._intialize=="undefined"){
		Car.prototype.showColor=function(){
			alert(this.color);
		};
	}
	Car._initialized=true;
	
}
var oCar1=new Car("red",4,23);
var oCar2=new Car("blue",4,25);
oCar1.showColor();//red
oCar2.showColor();//blue

6、混合工厂方式
创建方式与工厂方式很相似，不过使用new实例化对象。一般情况下，应该避免使用这种方式。

一般使用构造函数原型方式定义类，即用构造函数定义对象的所有非函数属性，用原型方式定义对象的函数属性。结果所有函数只创建一次，而每个对象都有自己的对象属性实例。