Safari + UpdatePanel + Panel + CalendarExtender, change Panel visible

Hi all,

This is the code that's not working in Safari 4:

<%@ Page Language="C#" AutoEventWireup="true" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>

<!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" >

    <script runat="server" >      
        void ddlPeriodSelection_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (ddlPeriodSelection.SelectedValue != "Time_period")
            {
                pnlTimePeriodSelection.Visible = false;
            }
            else
            {
                pnlTimePeriodSelection.Visible = true;
            }
        }      
   </script>

<head id="Head1" runat="server">
    <title>Untitled Page</title>    
</head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <div> 
                How long connection should be available? 
                                   
               <asp:DropDownList ID="ddlPeriodSelection" runat="server"  
                    onselectedindexchanged="ddlPeriodSelection_SelectedIndexChanged" AutoPostBack=true>
                    <asp:ListItem Value="One_day" Text="Today" />                               
                    <asp:ListItem Value="Time_period" Text="Select date" />
              </asp:DropDownList>
                    
              <asp:Panel runat="server" ID="pnlTimePeriodSelection" Visible="false"> 
                Please select exact date:          
                <asp:TextBox runat="server" ID="tbDateFrom" Width="70px" />            
                <ajaxToolkit:CalendarExtender ID="calendarButtonExtenderFrom" runat="server" TargetControlID="tbDateFrom" />
             </asp:Panel>                  
                   
                </div>
            </div>
        </ContentTemplate>
        </asp:UpdatePanel>
    </form>
</body>
</html>

After the selection of second option it stops refresh updatepanel. Calendar is also not rendered.

Could someone suggest how can i fix it ?

Thanks

------------------------------------

I put the following in a separate .js file:

Sys.Browser.WebKit = {}; //Safari 3 is considered WebKit
if (navigator.userAgent.indexOf('WebKit/') > -1) {
    Sys.Browser.agent = Sys.Browser.WebKit;
    Sys.Browser.version = parseFloat(navigator.userAgent.match(/WebKit\/(\d+(\.\d+)?)/)[1]);
    Sys.Browser.name = 'WebKit';
}

I then referenced the script on the masterpage where the control is located:

http://forums.asp.net/t/1413064.aspx

Solution is here http://forums.asp.net/p/1252014/2392110.aspx