DateFrom and DateTo textbox auto clear when button BtnExportReport is clicked

DateFrom and DateTo textbox auto clear when button BtnExportReport is clicked

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="ReportCollection.aspx.cs" Inherits="ReportCollection" %>

<%@ Register Assembly="Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" Namespace="Microsoft.Reporting.WebForms" TagPrefix="rsweb" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<%@ Register Assembly="TimePicker" Namespace="MKB.TimePicker" TagPrefix="Tpc1" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder2" runat="Server">
    <title>Collection Report</title>
    <meta name="viewport" content="width = device-width, initial-scale = 1.0, minimum-scale = 1.0, maximum-scale = 1.0, user-scalable = no" />


    <%-- ============================ Start Script ====================================== --%>

    <%-- Start Sweet Alert --%>
    <script src="https://unpkg.com/sweetalert/dist/sweetalert.min.js"></script>
    <%-- End Sweet Alert --%>

    <%-- Start Date --%>
    <link type="text/css" href="../Scripts/jquery-ui-1.8.19.custom.css" rel="stylesheet" />
    <script src="../Scripts/jquery-1.7.2.min.js"></script>
    <script type="text/javascript" src="../Scripts/jquery-ui-1.8.19.custom.min.js"></script>
    <%-- End Date --%>


    <%-- Start GridView Scroll --%>
    <script src="../GridViewScrollBothSide/jquery-1.9.1.min.js"></script>
    <script src="../GridViewScrollBothSide/JavaScript.js"></script>
    <script src="../GridViewScrollBothSide/GridViewScrollBothSide.js"></script>
    <%-- End Grid View Script --%>

    <%-- Start ListBox Sumo Select --%>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/5.3.2/jquery.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery.sumoselect/3.4.9/jquery.sumoselect.min.js"></script>
    <link href="https://cdnjs.cloudflare.com/ajax/libs/jquery.sumoselect/3.4.9/sumoselect.min.css" rel="stylesheet" />
    <%-- End ListBox Sumo Select --%>

    <%-- ============================ End Script ====================================== --%>