<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <style>
       /* 填写样式 */
    </style>
</head>

<body>
    <!-- 填写标签 -->
    <script type="text/javascript">
        // 填写JavaScript
        function _factorial(number) {
            if(number ==1){
                return 1
            }
            return number * _factorial(number-1)
}
    </script>
</body>

</html>