for (var i = 0; i < 10; i++) {                arr.push(i)            }            function arrSlice(arr, num) {                var arr1 = [];                for (var i = 0; i < arr.length / num; i++) {                    arr1.push(arr.slice(num * i, num * i + num))                }                return arr1;            }

var arr3=[];

arr3 = arrSlice(arr, 2) //将数组弄成下标分组