​x
 
<!DOCTYPE html>
<html>
<body>
​
<p id="demo"></p>
​
<script>
var person = {
  firstName: "Bill",
  lastName : "Gates",
  id     : 678,
};
person.name = function() {
  return this.firstName + " " + this.lastName;
};
​
document.getElementById("demo").innerHTML =
"My friend is " + person.name(); 
</script>
​
</body>
</html>
​