What the difference between this

Question

function person(name, age) {
this.name= name;
this.age = age;
this.yearOfBirth = bornYear;
}
function bornYear() {
return 2016 - this.age;
}

var p = new person("A", 22);

document.write(p.yearOfBirth());

And this function person(name, age) {
this.name = name;
this.age = age;
this.changeName = function (name) {
this.name = name;
}
}

var p = new person("David", 21);
p.changeName("John");

document.write(p.name);

.which is best to use

Answer 1

The top one isn't going to work how you would expect it to. The 'this.age' in the bornYear function is a variable that only the bornYear function knows about, unless there's some "this" JavaScript magic that I don't know about yet. I assume you were asking about the difference in the functions.