Add custom css class to WooCommerce checkout fields

Question

I would like to be able to add a custom CSS class to my WooCommerce checkout fields. I'm using twitter Bootstrap and I would like to be able to use their .form-control class. I looked in the woocommerce templates folder in `form-billing.php` but I'm not sure where to add the `.form-control` class to each text field. Here is the code for `form-billing.php` ```

cart->ship_to_billing_address_only() && WC()->cart->needs_shipping() ) : ?>

checkout_fields['billing'] as $key => $field ) : ?>

Accepted Answer

icc97's answer is almost there but doesn't work.

I took icc97's answer, and debugged it:

```
add_filter('woocommerce_checkout_fields', 'addBootstrapToCheckoutFields' );
public function addBootstrapToCheckoutFields($fields) {
    foreach ($fields as &$fieldset) {
        foreach ($fieldset as &$field) {
            // if you want to add the form-group class around the label and the input
            $field['class'][] = 'form-group';

// add form-control to the actual input
            $field['input_class'][] = 'form-control';
        }
    }
    return $fields;
}
```

Add custom css class to WooCommerce checkout fields

Solution

Problem