WooCommerce : Custom validation on checkout page for First and Last names to Contain Only Letters.

Customer having name “1234” has placed order on your Woocommerce site?

We are in 21st century, but it’s still not possible that a human being having a name like 1234 or any other number.
Woocommerce allow to fill user information on it’s checkout page. It also allow create user account at time of checkout. on checkout page their are many fields provided by woocommerce which may have input type number or text.

Woocommerce allow user to fill number instead of text in first name and last name field which not look so good.
because name having number in it look like fake details. Which may look like unsafe on site too.

It not look good because name can’t contain number so for validating it just use 'woocommerce_after_checkout_validation ' hook to add custom validation rules and error messages for this.

Example :

function ValidateFirstnameLastname( $fields, $errors ){
  if ( preg_match( '/\\d/', $fields['billing_first_name'] ) || preg_match( '/\\d/', $fields['billing_last_name'] )  ){
    $errors->add('validation','Your First name or Last name contains a number. Really?' );
  }
}
add_action('woocommerce_after_checkout_validation','ValidateFirstnameLastname',99,2);

Enjoy