my $BusUrl = $contact->getElementsByTagName( "BusinessUrl" );

# check if tag is defined and has children
if (defined $BusUrl && $BusUrl->hasChildNodes) {
  $bus_url = $BusUrl->item( 0 )->getChildAtIndex( 0 )->getData();
}
# otherwise assign an empty string
else {
  $bus_url = '';
}