onkeypress 事件 的用法、 textbox 使用者無法在輸入框中鍵入數字，

Internet Explorer 使用 event.keyCode 取回被按下的字元，而 Netscape/Firefox/Opera 使用 event.which。

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default5.aspx.cs" Inherits="Default5" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

  

<script type="text/javascript">

        function noNumbers(e) {
            var keynum
            var keychar
            var numcheck

          
            alert(window.event);
            if (window.event) // IE
            {
                keynum = e.keyCode
            }
            else if (e.which) // Netscape/Firefox/Opera
            {
                
                keynum = e.which
            }
            keychar = String.fromCharCode(keynum)
            
            numcheck = /\d/
            return !numcheck.test(keychar)
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
         <input type="text" onkeypress="return noNumbers(event)" />
    </div>
    </form>
</body>
</html>