问在woocommerce的Myaccount页面中仅允许名称字段中的字母

EN

add_filter( 'woocommerce_checkout_fields' , 'custom_override_checkout_fields' );

function custom_override_checkout_fields( $fields ) {
$fields['first_name']['placeholder'] = '21343';
$fields['first_name']['label'] = 'name';
$fields['first_name']['pattern'] = '[A-Za-z]';
return $fields;
}

add_action('woocommerce_process_myaccount_field_billing_last_name','billing_last_name_field_validation' );
function billing_last_name_field_validation(  ){
   /* print_r($_POST);
    die;*/


   $value = $_POST['billing_last_name'];
    if (!preg_match("/^[a-zA-Z]+$/", $value) ){       
        wc_add_notice( __( '<strong>Lastname should contain only letters</strong>' ), 'error' );
    }
    return $value; 
}