For loop without incrementing in iteration statement

Question

I just wanted to ask whether this is valid as this is the only way my script works as expected:

for (var j = 0; j < items.length; j) {
    for (var k = 1; k <= 3; k++) {
        $(items.eq(j)).appendTo('.col'+k);
        j++;
    }
}

notice the j that is not incrementing inside the for statement.

If I increment j, the loop ignores every 4th div for some reason and I can't explain the reason.

Here's a demo of this script.

My main question is whether this is a valid method, and if it's not, do you have a better solution for distributing the divs in each column?

Answer 1

A more natural approach would be iterate items directly:

$(".item").each(function(n) {
    $(this).appendTo('.col' + (n % 3 + 1));
});

The modulus operator % makes n cycle over the values 0, 1, 2, 0, 1, 2 etc.