You want to 'inherit' from Person's prototype object:
var Person = function (name) {
this.name = name;
this.type = 'human';
};
Person.prototype.info = function () {
console.log("Name:", this.name, "Type:", this.type);
};
var Robot = function (name) {
Person.apply(this, arguments);
this.type = 'robot';
};
Robot.prototype = Person.prototype; // Set prototype to Person's
Robot.prototype.constructor = Robot; // Set constructor back to Robot
person = new Person("Bob");
robot = new Robot("Boutros");
person.info();
// Name: Bob Type: human
robot.info();
// Name: Boutros Type: robot