Custom dropdown selector showing or hiding other Checkout custom fields

Question

I use this code to create custom checkout fields and reorder fields:

add_filter( 'woocommerce_checkout_fields', 'custom_checkout_billing_fields' );
function custom_checkout_billing_fields( $fields ) {

// 1. Creating the additional custom billing fields

    // The "status" selector
    $fields['billing']['billing_status']['type'] = 'select';
    $fields['billing']['billing_status']['class'] = array('form-row-wide, status-select');
    $fields['billing']['billing_status']['required'] = true;
    $fields['billing']['billing_status']['label'] = __('User status', 'my_theme_slug');
    $fields['billing']['billing_status']['placeholder'] = __('Chose an option', 'my_theme_slug');
    $fields['billing']['billing_status']['options'] = array(
        '' => 'Chose an option',
        '1' => 'Legal entity',
        '2' => 'Individual'
    );

    // The "Serial ID" text field
    $fields['billing']['billing_number_id']['type'] = 'text';
    $fields['billing']['billing_number_id']['class'] = array('form-row-wide', 'status-group1');
    $fields['billing']['billing_number_id']['required'] = true;
    $fields['billing']['billing_number_id']['label'] = __('Serial ID', 'my_theme_slug');
    $fields['billing']['billing_number_id']['placeholder'] = __('Enter your Serial ID', 'my_theme_slug');

    // Customizing 'billing_company' field ['required']
    $fields['billing']['billing_company']['required'] = false;

    // The "Serial ID" text field
    $fields['billing']['billing_serial']['type'] = 'text';
    $fields['billing']['billing_serial']['class'] = array('form-row-wide', 'status-group1');
    $fields['billing']['billing_serial']['required'] = false;
    $fields['billing']['billing_serial']['label'] = __('Serial ID', 'my_theme_slug');
    $fields['billing']['billing_serial']['placeholder'] = __('Enter your Serial ID', 'my_theme_slug');


// 2. Customizing 'billing_email' and 'billing_phone' fields ['class']

    $fields['billing']['billing_email']['class'] = array('form-row-first', 'status-group1');
    $fields['billing']['billing_phone']['class'] = array('form-row-last', 'status-group1');


// 3. Ordering the billing fields

    $fields_order = array(
        'billing_first_name', 'billing_last_name', 'billing_email',
        'billing_phone',      'billing_address_1', 'billing_address_2',
        'billing_postcode',   'billing_city',      'billing_country',
        'billing_status',
        'billing_company',   'billing_number_id',  'billing_serial'
    );
    foreach($fields_order as $field) $ordered_fields[$field] = $fields['billing'][$field];

    $fields['billing'] = $ordered_fields;


// Returning Checkout customized billing fields

    return $fields;

}

The conditional mechanism:

1. By default, the billing_status dropdown selector will be on Individual option value and will show only billing_serial custom field.
2. When the billing_status dropdown selector will switched to "Company"** option value , 2 more fields will appear:
   • billing_company existing field (before billing_serial)
   • billing_number_id custom fields (at the end)

How can I achieve this?

Thanks

---

Reference: WooCommerce - Checkout conditional fields for different persons custom status

Answer 1

For WooCommerce 3+ (update):

Since WooCommerce 3.0 checkout fields have changed a little bit so is not possible to reorder fields as before.

There is a new 'priority' argument that handle fields order, for checkout fields and my account fields as well.

Below I am just updating the part related to ordering fields:

## 3. Ordering the billing fields

// Set the order of the fields
$billing_fields_new_order = array(
    'billing_first_name', 'billing_last_name', 'billing_email',
    'billing_phone',      'billing_address_1', 'billing_address_2',
    'billing_postcode',   'billing_city',      'billing_country',
    'billing_status',
    'billing_company',   'billing_number_id',  'billing_ser_id'
);

$count = 0;
$priority = 10;

// Updating the 'priority' argument
foreach($billing_fields_new_order as $field_name){
    $count++;
    $fields['billing'][$field_name]['priority'] = $count * $priority;
}

// END: returning the customized checkout fields
return $fields;

Reference: Reordering checkout fields in WooCommerce 3

---

Original answer:

Here is a solution with a jQuery/JS script to make working the conditional mechanism just as you expect… The php code is completed with some necessaries functions…

PHP code (goes in function.php):

// Registering external jQuery/JS file
function cfields_scripts() {
    
    /* IMPORTANT NOTE: For a child theme replace get_template_directory_uri() by get_stylesheet_directory_uri()
                       The external cfields.js file goes in a subfolder "js" of your active child theme or theme.*/
    
    wp_enqueue_script( 'checkout_script', get_template_directory_uri().'/js/cfields.js', array('jquery'), '1.0', true );
}
add_action( 'wp_enqueue_scripts', 'cfields_scripts' );


add_filter( 'woocommerce_checkout_fields', 'custom_checkout_billing_fields' );
function custom_checkout_billing_fields( $fields ) {

// 1. Creating the additional custom billing fields

    // The "status" selector
    $fields['billing']['billing_status']['type'] = 'select';
    $fields['billing']['billing_status']['class'] = array('form-row-wide, status-select');
    $fields['billing']['billing_status']['required'] = true;
    $fields['billing']['billing_status']['label'] = __('User status', 'my_theme_slug');
    $fields['billing']['billing_status']['placeholder'] = __('Chose an option', 'my_theme_slug');
    $fields['billing']['billing_status']['options'] = array(
        '1' => __( 'Individual', '' ),
        '2' => __( 'Company', '' )
    );

    // Customizing 'billing_company' field ['required']
    $fields['billing']['billing_company']['required'] = false;
    $fields['billing']['billing_company']['class'] = array('form-row-wide', 'status-group2');

    // The "Number ID" text field
    $fields['billing']['billing_number_id']['type'] = 'text';
    $fields['billing']['billing_number_id']['class'] = array('form-row-wide');
    $fields['billing']['billing_number_id']['required'] = true;
    $fields['billing']['billing_number_id']['label'] = __('Number ID', 'my_theme_slug');
    $fields['billing']['billing_number_id']['placeholder'] = __('Enter your Number ID', 'my_theme_slug');

    // The "Serial identification" text field
    $fields['billing']['billing_ser_id']['type'] = 'text';
    $fields['billing']['billing_ser_id']['class'] = array('form-row-wide', 'status-group2');
    $fields['billing']['billing_ser_id']['required'] = false;
    $fields['billing']['billing_ser_id']['label'] = __('Serial identification', 'my_theme_slug');
    $fields['billing']['billing_ser_id']['placeholder'] = __('Enter your Serial identification', 'my_theme_slug');


// 3. Ordering the billing fields

    $fields_order = array(
        'billing_first_name', 'billing_last_name', 'billing_email',
        'billing_phone',      'billing_address_1', 'billing_address_2',
        'billing_postcode',   'billing_city',      'billing_country',
        'billing_status',
        'billing_company',   'billing_number_id',  'billing_ser_id'
    );
    foreach($fields_order as $field) $ordered_fields[$field] = $fields['billing'][$field];

    $fields['billing'] = $ordered_fields;


// Returning Checkout customized billing fields

    return $fields;

}


// Process the checkout
add_action('woocommerce_checkout_process', 'my_custom_checkout_field_process');
function custom_checkout_field_process() {
    // Check if set, if its not set add an error.
    if ( ! $_POST['billing_number_id'] )
        wc_add_notice( __( 'Please enter your Number ID.', 'my_theme_slug' ), 'error' );
    if ( ! $_POST['billing_ser_id'] )
        wc_add_notice( __( 'Please enter your Serial id.' , 'my_theme_slug' ), 'error' );
}

// Update the order meta with field value
add_action( 'woocommerce_checkout_update_order_meta', 'custom_checkout_field_update_order_meta' );
function custom_checkout_field_update_order_meta( $order_id ) {
    if ( ! empty( $_POST['billing_number_id'] ) )
        update_post_meta( $order_id, 'billing_number_id', sanitize_text_field( $_POST['billing_number_id'] ) );
    if ( ! empty( $_POST['billing_ser_id'] ) )
        update_post_meta( $order_id, 'billing_ser_id', sanitize_text_field( $_POST['billing_ser_id'] ) );
}


// Display field value on the order edit page
add_action( 'woocommerce_admin_order_data_after_billing_address', 'custom_checkout_field_display_admin_order_meta', 10, 1 );
function custom_checkout_field_display_admin_order_meta($order){
    echo '<p><strong>'.__('My number ID').':</strong> ' . get_post_meta( $order->id, 'billing_number_id', true ) . '</p>';
    echo '<p><strong>'.__('My serial identification').':</strong> ' . get_post_meta( $order->id, 'billing_ser_id', true ) . '</p>';
}

Javascript cfields.js code (external file):

// This file named "cfields.js" goes in a subfolder "js" of your active child theme or theme

jQuery(document).ready(function($){

    $('#billing_company_field').hide(function(){
        $(this).removeClass("validate-required");
    });
    $('#billing_ser_id_field').hide(function(){
        $(this).removeClass("validate-required");
    });
    $("#billing_number_id_field").addClass("validate-required");

    $("#billing_status").change(function(){
        if($("#billing_status option:selected").val() == "2"){
            $('#billing_company_field').show(function(){
                $(this).addClass("validate-required");
            });
            $('#billing_ser_id_field').show(function(){
                $(this).addClass("validate-required");
            });
        } else if($("#billing_status option:selected").val() == "1"){
            $('#billing_company_field').hide(function(){
                $(this).removeClass("validate-required");
            });
            $('#billing_ser_id_field').hide(function(){
                $(this).removeClass("validate-required");
            });
        }

    });

});

All this code has been tested and works