i have this code in aspx page

<div id=date_check visible=true runat=server>
          <strong>Check-In Date</strong> <asp:TextBox  ID="txt_checkin"  runat="server" onchange="checkdate(this);"></asp:TextBox>
<a  href="javascript:calendar_window=window.open('calendar.aspx?form1=form1.txt_checkin','calendar_window','width=554,height=488');calendar_window.focus()">
<img alt=""  src="images/calendar.png"    />  
        </a> 
              
  <strong>Check-Out Date</strong> <asp:TextBox  ID="txt_checkout"  runat="server" onchange="checkdate(this);"></asp:TextBox>
<a href="javascript:calendar_window=window.open('calendar.aspx?form1=form1.txt_checkout','calendar_window','width=554,height=488');calendar_window.focus()">
<img  alt=""  src="images/calendar.png"   />  
        </a>  
     
         </div>
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="calendar.aspx.vb" Inherits="gfln1.calendar_aspx" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title></title>
     <script runat="server">
    Protected Sub Calendar1_DayRender(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DayRenderEventArgs) Handles Calendar1.DayRender 
                  If e.Day.Date < DateTime.Today.Date Then 
                             e.Cell.Enabled = False        
                             e.Cell.ToolTip = "This date is not available"                      
                 End If 
    End Sub

Private Sub Calendar1_SelectionChanged(sender As Object, e As EventArgs)
    Dim strjscript As String = "<script language=""javascript"">"
    
        strjscript &= "window.opener." & _
              HttpContext.Current.Request.QueryString("form1") & ".value = '" & Calendar1.SelectedDate & "';window.close();"
        strjscript = strjscript & "</script" & ">" 'Don't Ask, Tool Bug

        Literal1.Text = strjscript  'Set the literal control's text to the JScript code

End Sub

</script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
     <asp:Calendar id="Calendar1" runat="server" 
                     OnSelectionChanged="Calendar1_SelectionChanged" 
                    
                     ShowTitle="true" DayNameFormat="FirstTwoLetters" 
                     SelectionMode="Day" BackColor="#ffffff" 
                     FirstDayOfWeek="Monday" BorderColor="#000000" 
                     ForeColor="#00000" Height="60" Width="120">
        <TitleStyle backcolor="#000080" forecolor="#ffffff" />
        <NextPrevStyle backcolor="#000080" forecolor="#ffffff" />
        <OtherMonthDayStyle forecolor="#c0c0c0" />
    </asp:Calendar>
    <asp:Literal id="Literal1" runat="server"></asp:Literal>
</div>
    </form>
</body>
</html>

but it showing old dates in FF but not in IE ,i wanted to disable old dates when open calender ..any work around

my latest code is like this

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="calendar.aspx.vb" Inherits="gfln1.calendar_aspx" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title></title>
     <script runat="server">
    Protected Sub Calendar1_DayRender(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DayRenderEventArgs) Handles Calendar1.DayRender 
                  If e.Day.Date < DateTime.Today.Date Then 
                             e.Cell.Enabled = False        
                             e.Cell.ToolTip = "This date is not available"                      
                 End If 
    End Sub

Private Sub Calendar1_SelectionChanged(sender As Object, e As EventArgs)
    Dim strjscript As String = "<script language=""javascript"">"
    
        strjscript &= "window.opener." & _
              HttpContext.Current.Request.QueryString("form1") & ".value = '" & Calendar1.SelectedDate & "';window.close();"
        strjscript = strjscript & "</script" & ">" 'Don't Ask, Tool Bug

        Literal1.Text = strjscript  'Set the literal control's text to the JScript code

End Sub

</script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
     <asp:Calendar id="Calendar1" runat="server" 
                     OnSelectionChanged="Calendar1_SelectionChanged" 
                    
                     ShowTitle="true" DayNameFormat="FirstTwoLetters" 
                     SelectionMode="Day" BackColor="#ffffff" 
                     FirstDayOfWeek="Monday" BorderColor="#000000" 
                     ForeColor="#00000" Height="60" Width="120">
        <TitleStyle backcolor="#000080" forecolor="#ffffff" />
        <NextPrevStyle backcolor="#000080" forecolor="#ffffff" />
        <OtherMonthDayStyle forecolor="#c0c0c0" />
    </asp:Calendar>
    <asp:Literal id="Literal1" runat="server"></asp:Literal>
</div>
    </form>
</body>
</html>

and here is another chunk of code

<div id=date_check visible=true runat=server>
          <strong>Check-In Date</strong> <asp:TextBox  ID="txt_checkin"  runat="server" onchange="checkdate(this);"></asp:TextBox>
<a  href="javascript:calendar_window=window.open('calendar.aspx?form1=form1.txt_checkin','calendar_window','width=554,height=488');calendar_window.focus()">
<img alt=""  src="images/calendar.png"    />  
        </a> 
              
  <strong>Check-Out Date</strong> <asp:TextBox  ID="txt_checkout"  runat="server" onchange="checkdate(this);"></asp:TextBox>
<a href="javascript:calendar_window=window.open('calendar.aspx?form1=form1.txt_checkout','calendar_window','width=554,height=488');calendar_window.focus()">
<img  alt=""  src="images/calendar.png"   />  
        </a>  
     
         </div>

Public Partial Class calendar_aspx
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    End Sub
    'Private Sub Calendar1_SelectionChanged(ByVal sender As Object, ByVal e As EventArgs)
    '    End Sub


    Private Sub Calendar1_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Calendar1.SelectionChanged
        Dim strjscript As String = "<script language=""javascript"">"
        strjscript &= "window.opener." & _
              HttpContext.Current.Request.QueryString("form1") & ".value = '" & _
              Calendar1.SelectedDate & "';window.close();"
        strjscript = strjscript & "</script" & ">" 'Don't Ask, Tool Bug

        Literal1.Text = strjscript  'Set the literal control's text to the JScript code

    End Sub
End Class

i want that it need to show current and above it dates and hide old one..this is working fine in IE but not in FF.any help