script let mean = 0 let num = 0 let i = 0 while i = 20 num += i i++ mean=numi-1 documentwrite1~20之间的数的平均值为$mean script不适用for

<script>
        let mean = 0
        let num = 0
        let i = 1
        while (i <= 20) {
            num += i
            i++
        }
        mean=num/20
        document.write(`1~20之间的数的平均值为${mean}`)
    </script>