Append array data to div of grid layout

var array1 = ["I", "II", "III"];
      var array2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18];
      var arrayout = [];
      var position = [1, 10, 17];

      var i1 = 0, j1 = 0;

      for (var i = 0; i < array1.length + array2.length  ; i++) {

          if (position.indexOf(i + 1) != -1) {
              arrayout.push(array1[i1])
              i1++;
          }
          else {

              arrayout.push(array2[j1]);
              j1++;
          }
      }