What nonsense is this? (Что за чушь?)

Question

In the test task shows the answer 24. Why?
(В тестовом задании показывает ответ 24. Почему?)
var arr = [1,2,3,4];
var x=1;
for (j=0;j<arr.lenght;j++){
x*=arr[j];
}
alert (x)

Answer 1

Not sure why you would call it nonsense without even trying to work out every iteration like in Ace's comment.