# Tests the start_hour, start_minute, end_hour, and end_minute
# pulldowns to verify that a consistent set of them have been
# specified, and that the start time (if specified) is before
# the end time.
sub validate_date_pulldowns {
  if (defined(param('end_hour'))) {
    return 0 unless defined(param('start_hour'));
    return 0 if param('start_hour') > param('end_hour');
  }
  if (defined(param('start_minute'))) {
    return 0 unless defined(param('start_hour'));
  }
  if (defined(param('end_minute'))) {
    return 0 unless defined(param('start_minute'));
    return 0 unless defined(param('end_hour'));
    return 0
      if param('start_hour') == param('end_hour') and
         param('start_minute') > param('end_minute');
  }
  return 1;
}