Trouble with JS challenge question (function calc())

Question

Why is the output 9?

function calc(i) {
return i*i;
}
for(var i =1; i<3; i++) {}
document.write(calc(i));

There's something really basic I'm missing here and I don't know what it is.
Thank you in advance!

Answer 1

for ( var i = 1; i < 3; i++ ) {} iterates until i = 3. Then you call calc with 3 -> it returns 9 and that gets printed...

Answer 2

it goes a bit different:
1.take the initial value,
2. do the loop body,
3. do the increment,
4. check the condition, if true go to 2...

Answer 3

Now I see, it was definitely a silly question. Thanks for the answers!

Answer 4

i < 3 means "iterate while i is minor than 3". When the i in your code is not anymore minor than 3? When it become equals to 3 after the last i++ (i=2+1).

Answer 5

for(var i=1 ;i<3 ;i++) {}

first i =1
iterated once making i = 2
iterated again making i = 3
so the idea is...loop stops iterating when i = 3 becoz meaning of the condition is(if i<3 , then do i++)
but by then" i "have the value of 3..

now calc(3) = 3*3 = 9