Bootstrap Modal Popup keep open on PostBack in ASP.Net

In This tutorial will show you how keep open Bootstrap Modal Popup when Postback in asp.net I have added one button inside  bootstrap model. in some requirement we need to save data and get some output on popup after button click in model popup .


source code-

 <form id="form1" runat="server">  
   <asp:ScriptManager ID="ScriptManager1" runat="server">  
   </asp:ScriptManager>  
   <div class="container">  
     <div class="row">  
       <h1>  
         Hello, world! Hello, world!</h1>  
       <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->  
       <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>  
       <!-- Include all compiled plugins (below), or include individual files as needed -->  
       <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>  
       <button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">  
         Launch demo modal  
       </button>  
       <asp:UpdatePanel ID="UpdatePanel1" runat="server">  
         <ContentTemplate>  
           <!-- Modal -->  
           <asp:Label ID="Label1" runat="server" Text=""></asp:Label><br />  
           <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel"  
             aria-hidden="true">  
             <div class="modal-dialog">  
               <div class="modal-content">  
                 <div class="modal-header">  
                   <button type="button" class="close" data-dismiss="modal" aria-label="Close">  
                     <span aria-hidden="true">&times;</span></button>  
                   <h4 class="modal-title" id="myModalLabel">  
                     Modal title</h4>  
                 </div>  
                 <div class="modal-body">  
                   <asp:TextBox ID="TextBox1" runat="server" placeholder="First Name" class="form-control"></asp:TextBox><br />  
                   <asp:TextBox ID="TextBox2" runat="server" placeholder="Middle Name" class="form-control"></asp:TextBox><br />  
                   <asp:TextBox ID="TextBox3" runat="server" placeholder="Last Name" class="form-control"></asp:TextBox><br />  
                 </div>  
                 <div class="modal-footer">  
                   <button type="button" class="btn btn-default" data-dismiss="modal">  
                     Close</button>  
                   <%--<button type="button" class="btn btn-primary">  
                     Save changes</button>--%>  
                   <asp:Button ID="Button1" runat="server" Text="Save" OnClick="Button1_Click" />  
              </div>  
               </div>  
             </div>  
           </div>  
         </ContentTemplate>  
       </asp:UpdatePanel>  
     </div>  
   </div>  
     <script type="text/javascript">  
       function openModal() {  
         $('#myModal').modal('show');  
       }  
 </script>  
   </form>  

code behind c#-

protected void Button1_Click(object sender, EventArgs e)

   {

       ScriptManager.RegisterStartupScript(this, this.GetType(), "Pop", "openModal();", true);

       Label1.Text = TextBox1.Text + " " + TextBox2.Text + " " + TextBox3.Text;


   }