Method __set

/**
 * Method to set certain otherwise inaccessible properties of the form field object.
 *
 * @param   string  $name   The property name for which to set the value.
 * @param   mixed   $value  The value of the property.
 *
 * @return  void
 *
 * @since   3.2
 */
public function __set($name, $value)
{
    if ($name === 'checked') {
        $value = (string) $value;
        $this->checked = $value === 'true' || $value == $name || $value === '1';
        return;
    }
    parent::__set($name, $value);
}