# Adding a field type - Fieldline 1.x documentation

> A complete example that registers a field type of your own, with its own check, in both checkouts.

Fieldline keeps a list of field types, and other plugins can add to it with the `fieldline_field_types` filter. A new type shows up in the **Type** dropdown, works in both checkouts, and its answers show on orders like any other.

## What a type is

Each type says how it looks in each checkout:

| Key | Meaning | Default |
|---|---|---|
| `label` | The name in the Type dropdown (required) | |
| `block` | The Checkout block's field type: `text`, `select` or `checkbox`, the only three it has | `text` |
| `classic` | The classic checkout's `woocommerce_form_field()` type, such as `text`, `textarea`, `select`, `radio`, `tel`, `url` or `date` | `text` |
| `options` | Whether the type has options (value => label), entered on the field's screen | `false` |
| `placeholder` | Whether the field's screen offers a placeholder | `true` |

Fieldline's own types (`text`, `textarea`, `select`, `checkbox`) can't be replaced.

## Example: a website address

```php
/**
 * Plugin Name: Website field for Fieldline
 */

add_action( 'fieldline_loaded', function () {
	// The type.
	add_filter( 'fieldline_field_types', function ( $types ) {
		$types['website'] = array(
			'label'   => __( 'Website address', 'my-plugin' ),
			'block'   => 'text',
			'classic' => 'url',
		);
		return $types;
	} );

	// Let browsers fill it in, in the Checkout block.
	add_filter( 'fieldline_block_field', function ( $args, $field ) {
		if ( 'website' === $field['type'] ) {
			$args['attributes'] = array( 'autocomplete' => 'url' );
		}
		return $args;
	}, 10, 2 );

	// Check it, in both checkouts.
	add_filter( 'fieldline_value_problem', function ( $problem, $field, $value ) {
		if ( '' === $problem && 'website' === $field['type'] && ! wp_http_validate_url( $value ) ) {
			/* translators: %s: field label */
			return sprintf( __( '%s must be a web address, starting with https://.', 'my-plugin' ), $field['label'] );
		}
		return $problem;
	}, 10, 3 );
} );
```

Activate it, and **Website address** is in the **Type** dropdown on WooCommerce → Checkout Fields.

## If your plugin is deactivated

Fields of your type are kept, with all their settings and answers, but Fieldline leaves them out of checkout until a plugin registers the type again. The list of fields says so under the field's name. That way a field is never shown in a shape it wasn't made for.

## Settings of your own

To store a setting on a field (say, a list of allowed domains for the website field), add a row to the field's screen with `fieldline_field_rows`, read it in `fieldline_posted_field`, and clean it in `fieldline_clean_field`. See **Filters and hooks**.

Source: https://extendiment.com/plugins/fieldline/docs/1.x/adding-a-field-type