Validation not working

Question

User-1499457942 posted

Hi

  I have below code but Required Field Validator is not working . Secondly i want Code textbox size should be small

<div class="modal-body">
                    <div class="form-group">
                            <label for="No">No</label>
                            <asp:TextBox ID="txtNo"  CssClass="form-control input-sm"  runat="server" ></asp:TextBox>
                            <asp:RequiredFieldValidator ID="rfv1" CssClass="alert-danger" 
                            ControlToValidate="txtNo" ValidationGroup="save-modal" 
                            SetFocusOnError="true" Display="Dynamic" runat="server" 
                            ErrorMessage="Please Enter code!!!"></asp:RequiredFieldValidator>

                            <label for="Description">Description</label>
                            <asp:TextBox ID="txtDescription"  CssClass="form-control input-lg" runat="server" ></asp:TextBox>
                            <asp:RequiredFieldValidator ID="rfv2" CssClass="alert-danger" 
                            ControlToValidate="txtDescription" ValidationGroup="save-modal" 
                            SetFocusOnError="true" Display="Dynamic" runat="server" 
                            ErrorMessage="Please Enter Category Description!!!"></asp:RequiredFieldValidator>

                    </div>
                </div>        

Thanks