OOPs in JAvascript

var User = function (fname, lname) {
  this.fname = fname;
  this.lname = lname;
  this.fullname = function(){
     console.log("Fullname is "+this.fname+" "+this.lname);
  };
};


var Member = function(memberId, fname, lname) {
  this.memberId = memberId;
  User.call(this, fname, lname);
};

Member.prototype = new User();


Member.prototype.getMemberDetails  = function(){
	console.log("ID is "+this.memberId);
	this.fullname();
};

u = new User("sriram", "ramakrishnan");
m = new Member("05085036","sriram", "ramakrishnan");
m.getMemberDetails();