[web2py] in link i will post a string

[pk]

Hi together,

i think it is a very small problem.
i need a stringvariable that i post to the function user in my default
controller when the user is clicking this link:

string = 'Anmelden'

<li class="page_item"><a class="loginframe" href="{{=URL(r=request,
c='default', f='user')}}">Anmelden</a></li>

how can i do this?

and how can i catch the string in the controller like this?

def user():
    mystring = request...

thanks for your help

peter