三元运算符号检查不起作用

Question

我正在使用三元运算符来检查用户输入是否为数字。但是，当我按下检查按钮时，无论我输入数字还是字母，都会显示警告信息，请输入一个数字＆＃34;。这是我的代码。

<label style = "font-size:40px">Please Enter A Number Here: </label><input type = "text" id = "num" style = "font-size:40px">
        <button type = "button" onclick = "check()">Check</button>
        <script>
        function check() { 
        var input = document.getElementById("num");
        var check = /^[0-9]*$/;
        (!check.test(input)) ? window.alert("You have only entered numeric characters! Please proceed to press one of the other buttons.") : window.alert("Please enter only numbers!")
        }
        </script>