数组遍利

ES6 forEach

var aaa=[1,3,2,-7,6]
aaa.forEach((i)=>console.log(i))

原生for循环

var arr=['apple','pear','orange','banana']
for(let i=0;i<arr.length;i++){
   console.log(arr[i])
}

for的升级版for-in

var arr=['apple','pear','orange','banana']
for(let i in arr){
   console.log(arr[i])
}