js创建对象的两种常用方式

一、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("Mike","John");
}

Car.prototype.showColor = function() {
alert(this.color);
};

var oCar1 = new Car("red",4,23);
var oCar2 = new Car("blue",3,25);

oCar1.drivers.push("Bill");

alert(oCar1.drivers);	//输出 "Mike,John,Bill"
alert(oCar2.drivers);	//输出 "Mike,John"

二、动态原型方式

function Car(sColor,iDoors,iMpg){
this.color = sColor;
this.doors = iDoors;
this.mpg = iMpg;
this.drivers = new Array("Mike","John");

if( typeof(Car._initialized) == "undefined" ){//注意：检测undefined类型只能用typeof方法
Car.prototype.showColor = function(){
alert(this.color);
}

Car._initialized = true;
}
}