i found Invalid callback or postback propety error when we are submitting the button, actually we used bootstrap template on aspx page. Please tell me how to remove thios error.
?<%@ page language="C#" masterpagefile="~/MasterPage.master" EnableEventValidation="false" ValidateRequest="false" CodeFile="~/Contact_us.aspx.cs" inherits="Contact_us" %> <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> <!--start contact--> <div class="contactmap"> <!--start info contact--> <div class="infocontact infocontactdark blue"> <div class="contentinfocontact"> <p class="titleinfocontact">SKYLINK HOLIDAY</p> <ul> <li><p><img alt="" src="img/contact/iconinfocontactaddress.png">B-113 Patel Garden Dwarka metro </p></li> <li><p><img alt="" src="img/contact/iconinfocontactphone.png">Telephone: +91 99 1123 4333</p></li> <li><p><img alt="" src="img/contact/iconinfocontactmail.png">Mail: [email protected]</p></li> </ul> </div> <div class="triangleinfocontact"> <span></span> </div> <!--start marker--> <div class="markercontactmap"> <div class="circlemarker"><div class="innercirclemarker"></div></div> <div class="trianglemarker"></div> </div> <!--end marker--> </div> <!--end info contact--> <!--google maps--> <div id="map-canvas" > <img src="img/tours/contactus.jpg" style="width:100%; height:500PX"/> </div> <!--google maps--> </div> <!--end contactmap--> <!--start page--> <section id="internalpage"> <!--start container--> <div class="container clearfix"> <!--start form--> <form class="contactform"> <div class="grid_4 red"> <ul> <li class="filterinputicon"><asp:Label ID="name_lbl" runat="server" Text="Name" Font-Bold="True" ForeColor="Black" Font-Size="Large"></asp:Label></li> <li><asp:TextBox ID="name_txt" runat="server"></asp:TextBox></li> </ul> </div> <div class="grid_4 orange"> <ul> <li class="filterinputicon"><asp:Label ID="Label1" runat="server" Text="Email" Font-Bold="True" ForeColor="Black" Font-Size="Large"></asp:Label></li> <li><asp:TextBox ID="email_txt" runat="server"></asp:TextBox></li> </ul> </div> <div class="grid_4 blue"> <ul> <li class="filterinputicon"><asp:Label ID="Label2" runat="server" Text="Mobile" Font-Bold="True" ForeColor="Black" Font-Size="Large"></asp:Label></li> <li><asp:TextBox ID="mbl_txt" runat="server"></asp:TextBox></li> </ul> </div> <div class="grid_12"> <asp:Label ID="DisplayMessage" runat="server" Visible="false" /> <asp:TextBox ID="msg_txt" runat="server" TextMode="MultiLine" ></asp:TextBox> </div> <div class="grid_12"> <asp:Button ID="send_btn" runat="server" Text="Send" OnClick="send_btn_Click"/> </div> </form> <!--end form--> </div> <!--end container--> </section> <!--end internal page--> </asp:Content>