// 原理： 用for把值重大到小遍历赋值到新数组
    function revarse(arr) {
    var newArr =[];
    for (var i = arr.length - 1; i >= 0; i--) {
        newArr[newArr.length] = arr[i];
    }
    return newArr;
    }
    var arr1 = revarse([1,2,3,4,5,6]);
    console.log(arr1)