for循环

let arr=["A","B","C","D","E","F"]; for(let i=0;i

for...of

遍历出数组中的每个值

let arr=["A","B","C","D","E","F"]; for(let item of arr){   console.log(item); }//A B C D E F

for..in

遍历出数组中每个值的下标

let arr=["A","B","D","E","F"]; for(let item in arr){   console.log(item); }//0 1 2 3 4 5

ES6新增for...of的用法

遍历出数组中每个值的键（下标）　　arr.keys()

let arr=["A","B","C","D","E","F"]; for(let item of arr.keys()){   console.log(item); } //0 1 2 3 4 5

遍历出数组中的每个值　　arr.values()

let arr=["A","B","C","D","E","F"]; for(let item of arr.values()){   console.log(item); } //A B C D E F

遍历出数组中的每个值，以及每个值对应的下标　　arr.entries()

let arr=["A","B","C","D","E","F"];for(let item of arr.entries()){  console.log(item);}/**[ 0, 'A' ][ 1, 'B' ][ 2, 'C' ][ 3, 'D' ][ 4, 'E' ][ 5, 'F' ]**/