通过原型继承创建一个新对象

inherit.js

function inherit(p){
	if(p ==null) throw TypeError();
	if(Object.create){
		return Object.create(p);
	}
	var t = typeof p;
	if(t !== "object" && t !== "function") throwTypeError();
	function f(){};
	f.prototype = p;
	return new f();
}