Constructors in Javascript

                                            function Person(first, last, age, eye) {
                                                this.firstName = first;
                                                this.lastName = last;
                                                this.age = age;
                                                this.eyeColor = eye;
                                              }
                                        
                                        

A Constructor is a "blueprint" for creating many objects of the same "type". The way to create an "object type", is to use an object constructor function. In the example above, function Person() is an object constructor function. In JavaScript, the thing called this is the object that "owns" the code. The value of this, when used in an object, is the object itself. In a constructor function this does not have a value. It is a substitute for the new object. The value of this will become the new object when a new object is created. Note that this is not a variable. It is a keyword. You cannot change the value of this.