Page refreshing when attempting to save TextBox values - asp.net

Question

I have a table with TextBoxes and I set an UpdatePanel to the table and set a button that should save my new TextBoxes' value to the database as a trigger. But, when I press the button the page refreshes.
<%# Page Title="" Language="C#" MasterPageFile="~/MaestroMaster.master" AutoEventWireup="true"
CodeFile="ProjectDetails.aspx.cs" Inherits="Default" EnableEventValidation="false" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder2" runat="Server">
<style type="text/css">
.style1
{
height: 68px;
}
</style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder3" runat="Server">
<asp:ScriptManager ID="ScriptManager" runat="server"></asp:ScriptManager>
<div class="cntr">
<h1>
פרטי הלקוח
</h1>
</div>
<br />
<asp:UpdatePanel ID="CustomerUpdatePanel">
<ContentTemplate>
<table id="CustomerDetailsTBL" class="table">
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoID" type="text" class="form-control" runat="server" maxlength="9">
<span class="input-group-addon">ת.ז</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoAddress" type="text" class="form-control" runat="server" maxlength="30">
<span class="input-group-addon">כתובת</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoFirstName" type="text" class="form-control" runat="server"
maxlength="15">
<span class="input-group-addon">שם פרטי</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoCity" type="text" class="form-control" runat="server" maxlength="15">
<span class="input-group-addon">עיר</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoLastName" type="text" class="form-control" runat="server" maxlength="15">
<span class="input-group-addon">שם משפחה</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoEmail" type="text" class="form-control" runat="server">
<span class="input-group-addon">דוא"ל</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoPhone" type="text" class="form-control" runat="server" maxlength="10">
<span class="input-group-addon">טלפון</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoFax" type="text" class="form-control" runat="server" maxlength="10">
<span class="input-group-addon">פקס</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoMobile" type="text" class="form-control" runat="server" maxlength="10">
<span class="input-group-addon">טלפון נייד</span>
</div>
</td>
<td>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoArchitectName" type="text" class="form-control" runat="server"
maxlength="15">
<span class="input-group-addon">שם האדריכל</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoArchitectMobile" type="text" class="form-control" runat="server"
maxlength="10">
<span class="input-group-addon">טלפון אדריכל</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoContractorName" type="text" class="form-control" runat="server"
maxlength="15">
<span class="input-group-addon">שם הקבלן</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoContractorPhone" type="text" class="form-control" runat="server"
maxlength="10">
<span class="input-group-addon">טלפון קבלן</span>
</div>
</td>
</tr>
<tr>
<td>
<div class="input-group">
<input id="ProjectInfoSupervisorName" type="text" class="form-control" runat="server"
maxlength="15">
<span class="input-group-addon">שם המפקח</span>
</div>
</td>
<td>
<div class="input-group">
<input id="ProjectInfoSupervisorPhone" type="text" class="form-control" runat="server"
maxlength="10">
<span class="input-group-addon">טלפון מפקח</span>
</div>
</td>
</tr>
</table>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ContentPlaceHolder3_SaveCustomerDetailsBTN" EventName="Click"/>
</Triggers>
</asp:UpdatePanel>

Answer 1

You do not have any button inside the UpdatePanel to trigger a dynamic update of the UpdatePanel content only, and then the control id that make the trigger not exist ContentPlaceHolder3_SaveCustomerDetailsBTN in this code you give