PHP strpos

[eluser]frist44[/eluser]
I'm trying to test if the string 'login' or 'join' is in my URL and if so, do set a session variable.

For just one, I have:

if (strpos(cur_url(), 'login') === FALSE) $this->set_prev_url();

however, if I add an "or" condition to put 'join', it'll write the session even when it's on the login, because the 'join' condition will be satisfied. How could I pass in a few strings and test the same condition?