Как присвоить выбранному radio button класс?
<div class="form-group<?php echo ($option['required'] ? ' required' : ''); ?>">
<label class="control-label"><?php echo $option['name']; ?></label>
<div id="input-option<?php echo $option['product_option_id']; ?>">
<?php foreach ($option['product_option_value'] as $option_value) { ?>
<div class="radio">
<label>
<input type="radio" name="option[<?php echo $option['product_option_id']; ?>]" value="<?php echo $option_value['product_option_value_id']; ?>" />
<?php echo $option_value['name']; ?>
<?php if ($option_value['price']) { ?>
(<?php echo $option_value['price_prefix']; ?><?php echo $option_value['price']; ?>)
<?php } ?>
</label>
</div>
<?php } ?>
</div>
</div>