Sub user(source As object,args As ServerValidateEventArgs)
if len(args.Value)<8 or len(args.Value)>16 then
<asp:Label runat="server" Text="请输入用户名:" />
<asp:TextBox id="txt1" runat="server" />
<asp:Button Text="提交" runat="server"/>
<asp:Label id="mess" runat="server"/>
Text="用户名必须介于 8 到 16 个字符之间!"