jQuery轮播图（模仿滑动窗口算法）

```
const status = [
  "left:0px;",
  "left:10px;",
  "left:20px;",
  "left:30px;",
  "left:40px;",
];
const list = $("#carousel > ul > li");
const len = list.length;
let pointer = 0;

function change(dir) {
  pointer = outRange(dir ? pointer+1 : pointer-1);
  for (let i = 0, len = status.length; i < len; i++)
    $(list[outRange(pointer + i)]).attr("style", status[i]);
}

function outRange(val) {
  return val >= len ? val % len : val < 0 ? len - 1 : val;
}

$("#bu1").click(function () {
  change(true);
});
$("#bu2").click(function () {
  change(false);
});

----------------------
function outRange2(val, max, min) {
  return val > max ? min : val < min ? max : val;
}
----------------------
function outRangeGen(max, min){
  return (val) =>{
    return val > max ? min : val < min ? max : val;
  }
}