I have this javasctipt class

```
function employee(name, jobtitle, born)
{
    this.name = name;
    this.jobtitle = jobtitle;
    this.born = born;
}

var fred = new employee("Fred Flintstone", "Caveman", 1970);
employee.prototype.salary = null;
fred.salary = 20000;
fred.notprototype = 1239;
console.log(fred);

```

now as you can see I added salary property using prototype but then I just added a property by using `fred.notprototype = 1239;` without the use of prototype. 

when I did the console.log on object fred I see notprototype there. So Is it wrong not to add the prototype? If it is then what difference is it making?