Could someone explain me how this code works line to line? Thanks.

Question

var count=0;
for(var i=0;i<3;i++){
count--;
for(var j=0;j<=2;j++){
count++;
}
}
alert(count);

Answer 1

You have three variables, all three are set to zero. For the first for loop if i is less than 3, then it will subtract 1 from count. Then it will add 1 to variable i.

Your next for loop does similar above, except if J is equal or less than 2 then it will add +1 to count. Then, it will add +1 to j.

The alert is outside of the for loop. This means that is not part of it and will execute as normal as if the fors didn't exist. alert looks like a pop-up but I don't see windows(), so msg. It will show what count variable integer is.

The fors will execute until they meet their conditional (which is the second segment of the code (>,<,<=,>=,=!, etc).

Answer 2

for i =0 inner for loop run 3 time
for i =1 inner for loop run 3 time
for i =2 inner for loop run 3 time
for i =0 count =-1 then for inner loop j=0,1,2 count=-1+3=2
then
for i =1 count =2-1=1 then for inner loop j=0,1,2 count=1+3=4
then
for i =2 count =4-1=3 then for inner loop j=0,1,2 count=3+3=6
so output alert as 6