constructor.js

function Person(firstName, lastName) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.showName = function() {
     console.log(this.firstName + ' ' + this.lastName);
  };
}

// Khi muốn tạo object person chỉ cần gọi constructor
var psn1 = new Person('Hoang', 'Pham');
var psn2 = new Person('Hoang', 'Nguyen');