var AAA = function(name, age) {	this.name = name ;	this.age = age;}AAA.prototype.getName = function() {	console.log(this.name);}AAA.prototype.getAge = function() {	console.log(this.age);}var BBB = function(name, age, comments) {	if(this instanceof BBB) {		AAA.call(this, name, age);		this.comments = comments;	} else{		return new BBB(name, age, comments);	}};BBB.prototype = new AAA();BBB.prototype.getComments = function() {	console.log(this.comments);}var bbb = BBB('mhp', 17, 'b');console.dir(bbb);bbb.getName();bbb.getAge();// 17bbb.getComments();// bconsole.log(BBB.prototype instanceof AAA);