More on objects.

<body>

            <p id="demo"></p>

                <script>

                    var person = {

                        firstName: "John",
                        lastName: "Carlsson",
                        fullName : function() {return this.firstName + " " + this.lastName;}
                        /*.this means that take another member from the same object to the other member
                        of the same object.*/

                    };

                    document.getElementById("demo").innerHTML = person.fullName();

                </script>

        </body>