jquery中如何获得服务器控件

jquery中 

$("#<%=StoreName.ClientID %>").focus(function() {
                $("#<%=Label5.ClientID %>").val("请输入真实的店铺名称");
                $("#<%=Label5.ClientID %>").css("color", "#666");
            });

html中

 <table>
                <tr>
                    <td>
                        店铺名称：
                    </td>
                    <td>
                        <asp:TextBox ID="StoreName" runat="server"></asp:TextBox>
                    </td>
                    <td>
                        <asp:Label ID="Label5" runat="server" Text=" 真实的店铺名称，0-10个字。（必填项）"></asp:Label>
                    </td>
                </tr>
            </table>