nerv_,
а что нужно поставить в аргументы split чтоб получить из
var arr = [
[1,2,3,4,5,6,7,8,9],
[10,11,12,13,14,15,16,17,18],
[19,20,21,22,23,24,25,26,27],
[28,29,30,31,32,33,34,35,36],
[37,38,39,40,41,42,43,44,45],
[46,47,48,49,50,51,52,53,54],
[55,56,57,58,59,60,61,62,63],
[64,65,66,67,68,69,70,71,72 ],
[73,74,75,76,77,78,79,80,81]
];
результат
var arr=[[[1, 2, 3], [10, 11, 12], [19, 20, 21]], [[4, 5, 6], [13, 14, 15], [22, 23, 24]], [[7, 8, 9], [16, 17, 18], [25, 26, 27]], [[28, 29, 30], [37, 38, 39], [46, 47, 48]], [[31, 32, 33], [40, 41, 42], [49, 50, 51]], [[34, 35, 36], [43, 44, 45], [52, 53, 54]], [[55, 56, 57], [64, 65, 66], [73, 74, 75]], [[58, 59, 60], [67, 68, 69], [76, 77, 78]], [[61, 62, 63], [70, 71, 72], [79, 80, 81]]]