foreach (keys %{$attribs}) {
next unless $_ =~ m/^(.*)\*$/;
my $key = $1;
- next unless $attribs->{$_} =~ m/^$re_exvalue$/;
+ next unless ($attribs->{$_} // '') =~ m/^$re_exvalue$/;
my ($charset, $value) = ($1, $2);
$value =~ s/%([0-9A-Fa-f]{2})/pack('C', hex($1))/eg;
if (length $charset) {