map小测试

var data_li = document.getElementById("data_li")

        let str = ''

        console.log(arr.length)

        arr.map((item, index) => {

            str += '<li>' +

            '<span>' + item.name + '</span>' +

            '<span>' + item.score + '</span>' +

            '</li>'

        })

        data_li.innerHTML = str