if(typeof Object.create!='function'){
		Object.create = function(o){
			var F = function(){};
			F.prototype = o;
			return new F();
		}
	}
var o = Object.create(a)





/**********/

function inheritPrototype(subType,superType){
	// 两个参数：子类型构造函数和超类型构造函数

	var prototype = object(superType.prototype);
	// 创建超类型原型的副本

	prototype.constructor = subType;
	// 为副本添加constructor属性，弥补重写原型失去默认constructor属性

	subType.prototype = prototype;
	// 创建的新对象赋值给子类型的原型
}





/*********/


function extend(base, sub) {

  var origProto = sub.prototype;
  sub.prototype = Object.create(base.prototype);
  for (var key in origProto)  {
     sub.prototype[key] = origProto[key];
  }
  // Remember the constructor property was set wrong, let's fix it
  sub.prototype.constructor = sub;
  // In ECMAScript5+ (all modern browsers), you can make the constructor property
  // non-enumerable if you define it like this instead
  Object.defineProperty(sub.prototype, 'constructor', {
    enumerable: false,
    value: sub
  });
}

// Let's try this
function Animal(name) {
  this.name = name;
}

Animal.prototype = {
  sayMyName: function() {
    console.log(this.getWordsToSay() + " " + this.name);
  },
  getWordsToSay: function() {
    // Abstract
  }
}

function Dog(name) {
  // Call the parent's constructor
  Animal.call(this, name);
}

Dog.prototype = {
    getWordsToSay: function(){
      return "Ruff Ruff";
    }
}

// Setup the prototype chain the right way
extend(Animal, Dog);

// Here is where the Dog (and Animal) constructors are called
var dog = new Dog("Lassie");
dog.sayMyName(); // Outputs Ruff Ruff Lassie
console.log(dog instanceof Animal); // true
console.log(dog.constructor); // Dog