FormAuthentication Cookie

Hi,
I have problem in Form Authentication Cookie. Below code works fine in case of removing web.config setting but I get "Request.Cookies[FormsAuthentication.FormsCookieName]" = NULL when web.config setting are enabled. So how can i achieve this type of functionality  when config settings are present.
Another case is that when web.config settings are enabled I can easily retrieve values of cookie from JAVASCRIPT. But not in code behind. Web.config settings are really required to achieve this type of functionality?

i am using the following code:
Storing cookie Values :

if (chkRemeberMe.Checked)
{                     
                        string strData = string.Format("{0}&a ...