HTTP_REFERER

[PythonistL]

I use the following view for user's log in
###################
def MyLogin(request):
    WrongID=0
    AllGood=1
    if request.POST:
        print "Refferer1 from POST",Refferer1
        try:
            u=users.get_object(Login__exact=request.POST['Login'])
        except users.UserDoesNotExist:
            WrongID=1
        if not WrongID and (u.Password==request.POST['Password']):
            return render_to_response('board/SuccessfulLogin', {'u':
u})
        else:
            return HttpResponse("Wrong ID or a password.")
    else:#first GET the LoginForm
            Refferer1= request.META['HTTP_REFERER']
            print "Refferer1 from GET",Refferer1
            manipulator = users.AddManipulator()
            errors = new_data = {}
            form = formfields.FormWrapper(manipulator, new_data,
errors)
            return render_to_response('board/LoginForm', {'form':form})
###################
and I would like to check 'HTTP_REFERER' so I use
Refferer1= request.META['HTTP_REFERER']
on line 15.
I want to use the same 'HTTP_REFERER' value I got from GET, in POST
part too ( line 5), but it is empty on line 5. The value is not saved
from GET ( line 15).
Can anybody explain WHY the value from GET part
(command on line 15 such as
Refferer1= request.META['HTTP_REFERER']
)
is not saved to POST?
Thank you
L.