var Person = {
  init: function(first_name, last_name) {
    this.first_name = first_name;
    this.last_name = last_name;
    return this;
  },
  full_name: function() {
    return this.first_name + " " + this.last_name;
  }
}

var daniel = Object.create(Person);
daniel.init("Daniel","Wagener");
console.log(daniel.full_name()); //Daniel Wagener