javascript的 new 运算符

function Person(name){
    this.name = name
}
Person.prototype.showName = function(){
    return this.name
}
var ly = new Person('ly')
ly.showName()  //返回ly

function lnew(){
    var obj = new Object() 
    var base= Array.prototype.shift.call(arguments)
    obj.__proto__ = base.prototype 
    var ret = base.apply(obj, arguments) 
    return typeof ret==='object'?ret:obj
}
var per = lnew(Person,'ly')
per.name //输出ly
per.showName() //输出ly