js实现数组内数据的上移和下移的实例

var swapItems = function(arr, index1, index2){　　arr[index1] = arr.splice(index2,1,arr[index1])[0]　　return arr}var arr = [1,2,3]var newArr = []upData (arr, index) {　　if (this.arr.length > 1 && index !== 0) {　　　　newArr = swapItems(arr, index, index - 1)　　}}downData (arr, index) {　　if (this.arr.length > 1 && index !== (this.arr.length - 1)) {　　　　newArr = swapItems(this.arr, index, index + 1)　　}}