js inherist call apply prototype

inherist.js

var ClassA = function(name){
	this.name = name || 'no name';
};

ClassA.prototype.sayName = function(){
	console.log('say name:' + this.name);
};

var ClassB = function(name, age){
	// this.new = ClassA;
	// this.new(name);
	// delete this.new;

	// ClassA.call(this, name);

	// ClassA.apply(this, [name]);

	ClassA.apply(this, arguments);//继承属性

	this.age = age;
};

ClassB.prototype = new ClassA();//继承方法

ClassB.prototype.sayAge= function(){
	console.log('say age:' + this.age);
};

var a = new ClassA('A');
var b = new ClassB('B', 1);

a.sayName();//say name:A
b.sayName();//say name:B
b.sayAge(); //say age:1