note 36025 added to str_replace

I wanna replace a question mark '?' by "<" out of a string. what should i do? I've tried the following, but they just won't work, any idea what i should do!? $text = str_replace( "?/f", "</f", $text ); // nothing happened $text = str_replace( "\?/f", "</f", $text ); //nothing happened. ---- Manual Page -- http://www.php.net/manual/en/str_replace.php Edit Note -- http://master.php.net/manage/user-notes.php?action=edit+36025 Delete Note -- http://master.php.net/manage/user-notes.php?action=delete+36025&report=yes Reject Note -- http://master.php.net/manage/user-notes.php?action=reject+36025&report=yes