老师，请帮忙优化一下，谢谢

来源：4-4 编程练习

Moomin6

2019-05-27 21:59:08

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>数字取整</title>
</head>
<body>
<script>
    //补充代码
    function numInt(num){
        var numNew;
        if(isNaN(num)){
            alert("输入的时间格式仅限为整数或浮点数");
            num = prompt("请输入本次运动时间");
        }
        while(!isNaN(num)){
            if(num > 20){
                numNew = Math.ceil(num);
            }else{
                numNew = Math.floor(num);
            }
            return numNew; break;
        }
    }
    var num = prompt("请输入本次运动时间");
    document.write("您本次运动时间为"+numInt(num)+"分钟");
</script>
</body>
</html>