JavaScript 构建类和创建对象的方式

1>工厂函数来创建对象(Factory)
     function createCar(){
var obj = new Object;
obj.name = "BWM";
obj.show = function(){
alert(this.name);
}
return obj;
}
var car1 = createCar();
var car2 = createCar();
car1.show();
car2.show();
2>构造函数创建对象(Constructor)
     function Car(name){
this.name = name;
this.show = function(){
alert(this.name);
}
}
Car.prototype.say = function(){
alert("hello");
}
var car = new Car("BMW");
car.show();
car.say();
3>原型（prototype）创建对象
      function Car(){}
Car.prototype.name = "BMW";
Car.prototype.show = function(){
alert(this.name);
}
Car.prototype.say = function(){
alert("Hiloo");
}
var car = new Car();
car.show(); car.say();
4>构造 && 原型：推荐使用，但是理解起来有点模糊
     /*
构造函数是来初始化非函数属性的
*/
function Car(name){
this.name = name;
}
Car.prototype.show = function(){
alert(this.name);
}
Car.prototype.say = function(){
alert("hiloo");
}
var car = new Car("BMW");
car.show(); car.say();
5>Dynamic Prototype：类似于java中类的创建，是学习过Java语言程序员常用的方式
    function Car(name){
this.name = name;
if(typeof Car._initialized == "undefined"){
Car.prototype.show = function(){
alert(this.name);
}
Car._initialized = true;//改变目的是，执行一次
}
}
var car = new Car("BMW");
car.show();