JS 混合构造函数 和 动态原型

混合构造函数, 就是 原型模式+普通构造函数方式

构造函数 定义对象的非函数属性.

原型方式 定义 对象的函数属性(方法)

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"

下面说下动态原型:

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

不管实例化多少个 car对象,那么 showColor函数 只初始化一次.