Hi Johan,
because of the nature of NetTalk, the "URLs" are most likely not terribly useful to you. However here are some answers;
in most procedures loc:parent will contain the name of the "parent procedure" - ie the one that "called" this one. For example, if you have a browse embedded on a form, then the form is the parent of the browse. If you have a "child browse" then the parent is, well, the parent browse, and so on.
the current URL is in p_web.Requestfilename
the RequestReferer is in p_web.RequestReferer
but both of these are usually more or less meaningless because of the nature of Ajax requests, the popup (and content body) systems, and so on. However in specific situations they may be useful.
Cheers
Bruce