## 遍历的方法 1. forEach 2. for in ~~~ var arr = [1, 2, 3, 4, 5]; for (let index in arr) { console.log(index);//获取数组的下标 } ~~~ 3. for of ~~~ for (let value of arr) { console.log(value); //获取值 } ~~~ 4. map ~~~ arr.map(function (value) { console.log(value); }) ~~~ 5. for