JS中prototype关键字的功能介绍及使用示例_javascript技巧



prototype 关键字可以为 JS原有对象 或者 自己创建的类 中添加方法或者属性。
也可以实现继承。
例子：
代码如下:








Number.prototype.add = function (num){
return this+num;
}
function but1_click(){
alert((3).add(8));
}

function Car(cColor,cWeight){
this.cColor = cColor;
this.cWeight = cWeight;
}
Car.prototype.drivers = new Array('zhangsan','lisi');
Car.prototype.work = function (cLong){
alert("我跑了"+cLong+"公里");
}
function but2_click(){
var c = new Car("red","5");
c.drivers.push('zhaoliu');
alert(c.drivers);
c.work(1);
}

function Rectangle(rWeight,rHeight){
this.rWeight = rWeight;
this.rHeight = rHeight;
if( typeof this._init == 'undefined'){
Rectangle.prototype.test = function (){
alert("test");
}
}
this._init = true;
}
function but3_click(){
var t = new Rectangle(6,8);
t.test();
}

function objectA(){
this.methodA = function (){
alert("我是A方法");
}
}
function objectB(){
this.methodB = function (){
alert("我是B方法");
}
}
objectB.prototype = new objectA();
function but4_click(){
var t = new objectB();
t.methodB();
t.methodA();
}

prototype 关键字的使用

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