Clientside validation not firing on FAPI forms.

The validation seems to be working as expected for fields on node edit forms.

This is not fixed. It works correctly for node edit forms, but not on a custom FAPI form that I created.

@attiks: Absolutely.

function restaurant_private_dining_form($form, &$form_state) {
  $current_restaurant_node = ''; // Hidden
  $recipient_email = ''; // Hidden

  $form['#attributes']['class'][] = 'private-dining-form';
  $form['description'] = array(
    '#type' => 'item',
    '#title' => t('Private Dining Request Form:'),
    '#description' => t('Description'),
  );

  $form['restaurant_name'] = array(
    '#type' => 'hidden',
    '#value' => $current_restaurant_node->title,
  );
  $form['recipient'] = array(
    '#type' => 'hidden',
    '#value' => $recipient_email,
  );
  $form['name'] = array(
    '#type' => 'fieldset',
    '#title' => t('Name'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['name']['first'] = array(
    '#type' => 'textfield',
    '#title' => t('First name:'),
    '#required' => TRUE,
  );
  $form['name']['last'] = array(
    '#type' => 'textfield',
    '#title' => t('Last name:'),
    '#required' => TRUE,
  );

  $form['phone_number'] = array(
    '#type' => 'telfield',
    '#title' => t('Phone number:'),
    '#required' => TRUE,
  );
  $form['email'] = array(
    '#type' => 'emailfield',
    '#title' => t('Your Email:'),
    '#required' => TRUE,
    '#rules' => array(
      'email',
    ),
  );
  $form['company'] = array(
    '#type' => 'textfield',
    '#title' => t('Company/Organization:'),
  );
  $form['date'] = array(
    '#type' => 'date',
    '#title' => t('Event date:'),
  );
  $form['time'] = array(
    '#type' => 'select',
    '#title' => t('Event time:'),
    '#options' => array(
      1200 => '12:00pm',
      1230 => '12:30pm',
      1300 => '1:00pm',
      1330 => '1:30pm',
      1400 => '2:00pm',
      1430 => '2:30pm',
      1500 => '3:00pm',
      1530 => '3:30pm',
      1600 => '4:00pm',
      1630 => '4:30pm',
      1700 => '5:00pm',
      1730 => '5:30pm',
      1800 => '6:00pm',
      1830 => '6:30pm',
      1900 => '7:00pm',
      1930 => '7:30pm',
      2000 => '8:00pm',
      2030 => '8:30pm',
      2100 => '9:00pm',
      2130 => '9:30pm',
      2200 => '10:00pm',
      2230 => '10:30pm',
      2300 => '11:00pm',
      2330 => '11:30pm',
    ),
    '#default_value' => 1700,
  );
  $form['guest_count'] = array(
    '#type' => 'select',
    '#title' => t('Number of Guests:'),
    '#options' => array(
      10 => '10',
      11 => '11',
      12 => '12',
      13 => '13',
      14 => '14',
      15 => '15',
      16 => '16',
      17 => '17',
      18 => '18',
      19 => '19',
      20 => '20',
      25 => '25+',
      30 => '30+',
      35 => '35+',
      40 => '40+',
      45 => '45+',
      50 => '50+',
      60 => '60+',
      70 => '70+',
      80 => '80+',
      90 => '90+',
      100 => '100+',
    ),
  );
  $form['special_event_subscribe'] = array(
    '#type' => 'checkbox',
    '#title' => t('I would like to receive special event info from this restaurant.'),
  );
  $form['comments'] = array(
    '#title' => t('Comments'),
    '#type' => 'textarea',
  );
  $form['how_did_you_hear'] = array(
    '#type' => 'select',
    '#title' => t('How did you hear about us?'),
    '#options' => array(
      'Frequent Customer',
      'Tour Operator',
      'Concierge',
      'CVB',
      'Advertisement',
      'Magazine',
      'Newspaper Article',
      'Meeting Planner',
      'Referred by a friend',
      'Other',
    ),
  );
  // This field should be hidden with CSS. It is placed here so that spam bots
  // will fill it.
  $form['validuser'] = array(
    '#type' => 'textfield',
    '#title' => t('What is the current web site\'s url?'),
    '#required' => FALSE,
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Submit',
  );
  return $form;
}

The validation gets fired on POST instead of on the client end. When I compare this to a node form, I can see that on the node form the client-side validation occurs on submit with no POST, whereas the form I posted in comment #6 posts back in typical Drupal core fashion before it presents the validation results.