/**
 * Fire the onInit event to initialise the captcha plugin.
 *
 * @param   string  $id  The id of the field.
 *
 * @return  boolean  True on success
 *
 * @since	2.5
 * @throws  \RuntimeException
 */
public function initialise($id)
{
    $arg = ['id' => $id];
    $this->update('onInit', $arg);
    return true;
}