Understanding nested for loops in javascript

Question

I\'m learning JavaScript at the moment on freecodecamp and they have an example for nested for loops in one of their excercises:

 var arr = [[1,2], [3,4], [5,6]]         


        

Answer 1

function multiply(arr) {
    var product = 1;

    for (var i = 0; i < arr.length; i++) {
        for (var j = 0; j < arr[i].length; j++) {
            product *= arr[i][j];
        }
    }

    return product;
}