Challenge Nesting For Loops

If you have a multi-dimensional array, you can use the same logic as the prior Challenge to loop through both the array and any sub-arrays. Here is an example:

    var arr = [
      [1,2], [3,4], [5,6]
    for (var i=0; i < arr.length; i++) {
      for (var j=0; j < arr[i].length; j++) {

This outputs each sub-element in arr one at a time. Note that for the inner loop, we are checking the .length of arr[i], since arr[i] is itself an array.