function form_example_states_form

States demo form.

This form shows off the #states system by dynamically showing parts of the form based on the state of other parts.

The basic idea is that you add a #states property to the element which is to be changed based on some action elsewhere on the form. The #states property lists a change which is to be made, and under what conditions that change should be made.

For example, in the 'tests_taken' form element below we have:

'#states' => array(
  'visible' => array(
    ':input[name="student_type"]' => array('value' => 'high_school'),
  ),
),

Meaning that the element is to be made visible when the condition is met. The condition is a combination of a jQuery selector (which selects the element we want to test) and a condition for that element. In this case, the condition is whether the return value of the 'student_type' element is 'high_school'. If it is, this element will be visible.

So the syntax is:

'#states' => array(
  'action_to_take_on_this_form_element' => array(
    'jquery_selector_for_another_element' => array(
      'condition_type' => value,
    ),
  ),
),

If you need an action to take place only when two different conditions are true, then you add both of those conditions to the action. See the 'country_writein' element below for an example.

Note that the easiest way to select a textfield, checkbox, or select is with the ':input' jquery shortcut, which selects any any of those.

There are examples below of changing or hiding an element when a checkbox is checked, when a textarea is filled, when a select has a given value.

See drupal_process_states() for full documentation.

See also

forms_api_reference.html

Related topics

File

form_example/form_example_states.inc, line 63

Code

function form_example_states_form($form, &$form_state) {
    $form['student_type'] = array(
        '#type' => 'radios',
        '#options' => array(
            'high_school' => t('High School'),
            'undergraduate' => t('Undergraduate'),
            'graduate' => t('Graduate'),
        ),
        '#title' => t('What type of student are you?'),
    );
    $form['high_school'] = array(
        '#type' => 'fieldset',
        '#title' => t('High School Information'),
        // This #states rule says that the "high school" fieldset should only
        // be shown if the "student_type" form element is set to "High School".
'#states' => array(
            'visible' => array(
                ':input[name="student_type"]' => array(
                    'value' => 'high_school',
                ),
            ),
        ),
    );
    // High school information.
    $form['high_school']['tests_taken'] = array(
        '#type' => 'checkboxes',
        '#options' => array(
            'SAT' => t('SAT'),
            'ACT' => t('ACT'),
        ),
        '#title' => t('What standardized tests did you take?'),
        // This #states rule says that this checkboxes array will be visible only
        // when $form['student_type'] is set to t('High School').
        // It uses the jQuery selector :input[name=student_type] to choose the
        // element which triggers the behavior, and then defines the "High School"
        // value as the one that triggers visibility.
'#states' => array(
            // Action to take.
'visible' => array(
                ':input[name="student_type"]' => array(
                    'value' => 'high_school',
                ),
            ),
        ),
    );
    $form['high_school']['sat_score'] = array(
        '#type' => 'textfield',
        '#title' => t('Your SAT score:'),
        '#size' => 4,
        // This #states rule limits visibility to when the $form['tests_taken']
        // 'SAT' checkbox is checked."
'#states' => array(
            // Action to take.
'visible' => array(
                ':input[name="tests_taken[SAT]"]' => array(
                    'checked' => TRUE,
                ),
            ),
        ),
    );
    $form['high_school']['act_score'] = array(
        '#type' => 'textfield',
        '#title' => t('Your ACT score:'),
        '#size' => 4,
        // Set this element visible if the ACT checkbox above is checked.
'#states' => array(
            // Action to take.
'visible' => array(
                ':input[name="tests_taken[ACT]"]' => array(
                    'checked' => TRUE,
                ),
            ),
        ),
    );
    // Undergrad information.
    $form['undergraduate'] = array(
        '#type' => 'fieldset',
        '#title' => t('Undergraduate Information'),
        // This #states rule says that the "undergraduate" fieldset should only
        // be shown if the "student_type" form element is set to "Undergraduate".
'#states' => array(
            'visible' => array(
                ':input[name="student_type"]' => array(
                    'value' => 'undergraduate',
                ),
            ),
        ),
    );
    $form['undergraduate']['how_many_years'] = array(
        '#type' => 'select',
        '#title' => t('How many years have you completed?'),
        // The options here are integers, but since all the action here happens
        // using the DOM on the client, we will have to use strings to work with
        // them.
'#options' => array(
            1 => t('One'),
            2 => t('Two'),
            3 => t('Three'),
            4 => t('Four'),
            5 => t('Lots'),
        ),
    );
    $form['undergraduate']['comment'] = array(
        '#type' => 'item',
        '#description' => t("Wow, that's a long time."),
        '#states' => array(
            'visible' => array(
                // Note that '5' must be used here instead of the integer 5.
                // The information is coming from the DOM as a string.
':input[name="how_many_years"]' => array(
                    'value' => '5',
                ),
            ),
        ),
    );
    $form['undergraduate']['school_name'] = array(
        '#type' => 'textfield',
        '#title' => t('Your college or university:'),
    );
    $form['undergraduate']['school_country'] = array(
        '#type' => 'select',
        '#options' => array(
            'UK' => t('UK'),
            'other' => t('Other'),
        ),
        '#title' => t('In what country is your college or university located?'),
    );
    $form['undergraduate']['country_writein'] = array(
        '#type' => 'textfield',
        '#size' => 20,
        '#title' => t('Please enter the name of the country where your college or university is located.'),
        // Only show this field if school_country is set to 'Other'.
'#states' => array(
            // Action to take: Make visible.
'visible' => array(
                ':input[name="school_country"]' => array(
                    'value' => t('Other'),
                ),
            ),
        ),
    );
    $form['undergraduate']['thanks'] = array(
        '#type' => 'item',
        '#description' => t('Thanks for providing both your school and your country.'),
        '#states' => array(
            // Here visibility requires that two separate conditions be true.
'visible' => array(
                ':input[name="school_country"]' => array(
                    'value' => t('Other'),
                ),
                ':input[name="country_writein"]' => array(
                    'filled' => TRUE,
                ),
            ),
        ),
    );
    $form['undergraduate']['go_away'] = array(
        '#type' => 'submit',
        '#value' => t('Done with form'),
        '#states' => array(
            // Here visibility requires that two separate conditions be true.
'visible' => array(
                ':input[name="school_country"]' => array(
                    'value' => t('Other'),
                ),
                ':input[name="country_writein"]' => array(
                    'filled' => TRUE,
                ),
            ),
        ),
    );
    // Graduate student information.
    $form['graduate'] = array(
        '#type' => 'fieldset',
        '#title' => t('Graduate School Information'),
        // This #states rule says that the "graduate" fieldset should only
        // be shown if the "student_type" form element is set to "Graduate".
'#states' => array(
            'visible' => array(
                ':input[name="student_type"]' => array(
                    'value' => 'graduate',
                ),
            ),
        ),
    );
    $form['graduate']['more_info'] = array(
        '#type' => 'textarea',
        '#title' => t('Please describe your graduate studies'),
    );
    $form['graduate']['info_provide'] = array(
        '#type' => 'checkbox',
        '#title' => t('Check here if you have provided information above'),
        '#disabled' => TRUE,
        '#states' => array(
            // Mark this checkbox checked if the "more_info" textarea has something
            // in it, if it's 'filled'.
'checked' => array(
                ':input[name="more_info"]' => array(
                    'filled' => TRUE,
                ),
            ),
        ),
    );
    $form['average'] = array(
        '#type' => 'textfield',
        '#title' => t('Enter your average'),
        // To trigger a state when the same controlling element can have more than
        // one possible value, put all values in a higher-level array.
'#states' => array(
            'visible' => array(
                ':input[name="student_type"]' => array(
                    array(
                        'value' => 'high_school',
                    ),
                    array(
                        'value' => 'undergraduate',
                    ),
                ),
            ),
        ),
    );
    $form['expand_more_info'] = array(
        '#type' => 'checkbox',
        '#title' => t('Check here if you want to add more information.'),
    );
    $form['more_info'] = array(
        '#type' => 'fieldset',
        '#title' => t('Additional Information'),
        '#collapsible' => TRUE,
        '#collapsed' => TRUE,
        // Expand the expand_more_info fieldset if the box is checked.
'#states' => array(
            'expanded' => array(
                ':input[name="expand_more_info"]' => array(
                    'checked' => TRUE,
                ),
            ),
        ),
    );
    $form['more_info']['feedback'] = array(
        '#type' => 'textarea',
        '#title' => t('What do you have to say?'),
    );
    $form['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Submit your information'),
    );
    return $form;
}