How to save the exported gridview file in a particular path having file name showing data and time

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"> </script>
    <script>

        function openDialog() {

            var input = $(document.createElement('input'));
            input.attr("type", "file");
            input.trigger('click');
            return false;
        }

    </script>

 <a Id="btnExport" onclick="openDialog()" Text="Export To Excel" >test</a>

http://www.c-sharpcorner.com/uploadfile/srseelam/file-download-with-save-as-dialog-box-from-browser/

if (!IsPostBack)
        {
            for (int month = 1; month <= 12; month++)
            {
                ddlMonths.Items.Add(new ListItem(month.ToString().PadLeft(2, '0'), month.ToString().PadLeft(2, '0')));
            }
            int year = (System.DateTime.Now.Year);
            for (int intCount = year; intCount >= 1980; intCount--)
            {
                ddlyear.Items.Add(intCount.ToString());
            }
        }



   <td>Month
                                            </td>
                                            <td>
                                                <asp:DropDownList ID = "ddlMonths" runat="server"></asp:DropDownList>

                                                <%--<asp:TextBox ID="txtmonth" runat="server"></asp:TextBox>--%>
                                            </td>
                                            <td>Year
                                            </td>
                                            <td>
                                                <%--<asp:TextBox ID="txtyear" runat="server"></asp:TextBox>--%>
                                                <asp:DropDownList ID="ddlyear" runat="server"></asp:DropDownList>
                                            </td>

https://www.codeproject.com/Questions/1184251/How-to-join-aspgrid-with-normal-tablerow

protected void ExportToExcel(object sender, EventArgs e)
        {
            gvDetails.AllowPaging = false;
            this.bind();
            Response.ClearContent();

            Response.AddHeader("content-disposition", "attachment; filename=Name.xls");
            Response.ContentType = "application/excel";
            System.IO.StringWriter sw = new System.IO.StringWriter();
            HtmlTextWriter htw = new HtmlTextWriter(sw);
            gvDetails.RenderControl(htw);
            string renderedGridView = sw.ToString();
            System.IO.File.WriteAllText(@"D:\New folder\Name.xls", renderedGridView);
            Response.Write(sw.ToString());
            Response.End();
        }
        protected void ExportToPdf(object sender, EventArgs e)
        {
           
            gvDetails.AllowPaging = false;
            this.bind();
            Response.ClearContent();
            string fileName = "Name";
            string dateFormat = "MMddyyyy";
            string timeformat = "HHmmss";
            string outPutFileName = string.Format("{0}_{1}_{2}.pdf", fileName, DateTime.Now.ToString(dateFormat), DateTime.Now.ToString(timeformat));
            Response.AddHeader("content-disposition", "attachment; filename=" + outPutFileName);


            Response.ContentType = "application/pdf";
            System.IO.StringWriter sw = new System.IO.StringWriter();
            HtmlTextWriter htw = new HtmlTextWriter(sw);

            gvDetails.RenderControl(htw);
            string renderedGridView = sw.ToString();
            System.IO.File.WriteAllText(@"D:\New folder\Name.pdf", renderedGridView);
            Response.Write(sw.ToString());
           
            Response.End();
        }
        protected void ExportToWord(object sender, EventArgs e)
        {
       
            using (StringWriter sw = new StringWriter())
            {
                using (HtmlTextWriter hw = new HtmlTextWriter(sw))
                {

                    gvDetails.AllowPaging = false;
                    this.bind();

                    gvDetails.RenderControl(hw);
                    StringReader sr = new StringReader(sw.ToString());
                    Document Doc = new Document(PageSize.A2, 10f, 10f, 10f, 0f);
                    HTMLWorker htmlparser = new HTMLWorker(Doc);
                    PdfWriter.GetInstance(Doc, Response.OutputStream);
                    Doc.Open();
                    htmlparser.Parse(sr);
                    Doc.Close();


                    Response.AddHeader("content-disposition", "attachment; filename=Name.doc");
                    Response.ContentType = "application/word";
                    
                    HtmlTextWriter htw = new HtmlTextWriter(sw);
                    gvDetails.RenderControl(htw);
                    string renderedGridView = sw.ToString();
                    System.IO.File.WriteAllText(@"D:\New folder\Name.doc", renderedGridView);
                    Response.Write(sw.ToString());
                    Response.End();
                }
            }
        }