js控制只能输入汉字的代码

 <style type="text/css">
 .charOnly  
        {
            ime-mode: disabled;
        }
</style>
<script language="javascript" type="text/javascript">
        function checkNum() {
            if ((event.keyCode < 48 || event.keyCode > 57) && event.keyCode != 43 && event.keyCode != 45)
                {
                    event.keyCode = 0;
                    event.returnValue = false;
                }
            }
 </script>
<asp:TextBox ID="txtMobile" runat="server" Width="260px" MaxLength="20"
CssClass="charOnly" onkeypress="checkNum()" ></asp:TextBox>
//或者
AutoCompleteType="Disabled" MaxLength="4" onkeypress="checkNum()"