将一个大的数组按照长度来划分成不同的小数组
var chunk = function (array, size) {
var result = [];
for (var x = 0; x < Math.ceil(array.length / size); x++) {
var start = x * size;
var end = start + size;
result.push(array.slice(start, end));
}
return result;
}
