JS中 prototype 关键字的使用

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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：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

<title>JS中 prototype 关键字的使用</title>

</head>

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();

}

</script>

<body>

<h2> prototype 关键字的使用 </h2>

<hr />

</body>

</html>