javascript继承对象

       function get(){
        alert(this.username+" : "+this.password);
    }
    function createObject(userName,pwd){
        var obj=new Object();
        obj.username=userName;
        obj.password=pwd;
        obj.get=get;
        return obj;
    }
    var object=createObject("小张","男");
    //object.get();


    //这里new出来的object的对象并不是最顶层的ojbect对象　
    function person(){
    
    }
    
    var per=new person();
    alert(typeof per.get);
    per.get();