JavaScript遍历数组、Map

<script>
        
        var arr = [3,4,5,6,34]
        //打印下标
        for(var x in arr){
            console.log(x)
        }
    </script>

   <script>
        var arr = [3,4,5,6,34]
        //打印数组
        for(var x of arr){
            console.log(x)
        }
    </script>

遍历map：