Why is a function called 20 times in angular?

Question

JavaScript

Here is the link: jsfiddle.net/1opjecjj
Why is the function called 20 times when entering and not just once, and why did they do that?

Answer 1

Because of $watch
habrahabr.ru/post/201832

Answer 2

You probably achieved this - jsfiddle.net/andreyzenkov/kcpt4614