js继承

//js继承

function classA(msg)

{

    this.age = 23;

    this.name = 'luowen';

    if(typeof classA._initialed == 'undefined')

        classA.prototype.sayHi = function(){alert('hello');}

    classA.initialed = true;



}



//原型冒充方法

function classB(msg,age)

{

    this.newMethod = classA;

    this.newMethod(msg);

    delete this.newMethod;

    //overwrite age property

    this.age = age;

}



//call方法实现

function classB(msg,age)

{

    classA.call(this,msg);

    this.age = age;

}



//apply方法实现

function classB(msg,age)

{

    classA.apply(this,arguments);

    this.age = age;

}



//原型链继承,确保没有参数

function classB(){

}

classB.prototype = new classA();

var oClassB = new classB();

console.log(oClassB.sayHi());