use strict;
+use warnings;
+
use CGI;
use C4::Auth;
use C4::Dates;
my $query = new CGI;
-my $op = $query->param('op');
+my $op = $query->param('op') || '';
my $dbh = C4::Context->dbh;
my $sth;
my ( $template, $loggedinuser, $cookie );
my $externalid = $query->param('externalid');
-my $alerttype = $query->param('alerttype');
+my $alerttype = $query->param('alerttype') || '';
my $biblionumber = $query->param('biblionumber');
( $template, $loggedinuser, $cookie ) = get_template_and_user(