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

<asp:Content ID="Home" ContentPlaceHolderID="Home" runat="server">
 
    <script type="text/javascript" language="javascript">
        function Validate() {
            var StartDate = document.getElementById('<%=txtstart.ClientID %>');           
            var EndDate = document.getElementById('<%=txtEnd.ClientID %>'); 
            if (StartDate.value =='') {
                alert("Pick Start Date");
               StartDate.focus();
                return false;
            }
      
            else if (EndDate.value =='') {
                alert("Pick End Date");
                EndDate.focus();
                return false;
            }

        }     
                  
    </script>   
<asp:TextBox ID="txtstart" runat="server" 
        style="margin-left: 0px" Width="148px" AutoPostBack="True"></asp:TextBox>
 <asp:TextBox ID="txtEnd" runat="server" AutoPostBack="True"></asp:TextBox>
 <asp:Button ID="btnNxt" runat="server" Text="Next" 
            Width="104px" onclick="btnNxt_Click" OnClientClick="javascript:return Validate()"/>
</asp:Content>