javascript在Asp.net驗證上傳檔案的檔案類型的

<%@ Page Language="C#" MasterPageFile="~/VQPMaster.master" AutoEventWireup="true" CodeFile="importQuotation.aspx.cs" Inherits="ImportExcel_importQuotation" Title="Untitled Page" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolderMain" Runat="Server">
<script type="text/javascript" src="../js/jquery-1.5.2.js"></script>
<script language="javascript" type="text/javascript">

        $(document).ready(function(){
var fileUpload = $("#<%=fileUpload.ClientID%>");
var txtEmail = $("#<%=txtEmail.ClientID%>");
var lblMessage = $("#<%=lblMessage.ClientID%>");
            lblMessage.text();
            $("#<%=btnSubmit.ClientID%>").click(function(){
if(fileUpload.val() == ""){
                    fileUpload.focus();
                    lblMessage.text("please upload file!");
return false;
                }
else // valid the upload file extension file name!
                {
var hash = {
'.XLS'  : 1,
'.XLSX' : 1
                  };
var re = /\..+$/;
var ext = fileUpload.val().toUpperCase().match(re);
if (!hash[ext]) {
                    lblMessage.text("Invalid filename, please select another file!");
return false;
                  }   
                }
if(txtEmail.val() == ""){
                    lblMessage.focus();
                    lblMessage.text("please input user email!");
return false;
                }


            })
            $("#btnReset").click(function(){
                 lblMessage.text("")               
            })
         })
</script>

<div id = "divUploadMain" style =" margin : 5px 0px 0px 4%; ">
<div id= "divFileUpload" style="height : 30px; margin-bottom : 5px;" >
            Quote&nbsp;&nbsp;&nbsp;&nbsp;File&nbsp;:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;<asp:FileUpload ID="fileUpload" runat="server" Width="464px" />
</div>
<div id = "divEmail" style="height : 30px; margin-top : 5px;">
            MAPS&nbsp;Email&nbsp;contact&nbsp;:
<asp:TextBox ID="txtEmail" runat="server" Width="464px"></asp:TextBox>
</div>
<div id="divBtns">
<asp:Button ID="btnSubmit" runat="server" Text="Submit"  />&nbsp;
<input id="btnReset" type="reset" value="Reset" />&nbsp;
<asp:Label ID="lblMessage" runat="server" ForeColor="Red" Visible="true" Text=""></asp:Label></div>
</div> 
</asp:Content>