Method help

/**
 * Writes a help button for a given option (opens a popup window).
 *
 * @param   string  $ref        The name of the popup file (excluding the file extension for an xml file).
 * @param   bool    $com        Use the help file in the component directory.
 * @param   string  $override   Use this URL instead of any other
 * @param   string  $component  Name of component to get Help (null for current component)
 *
 * @return  void
 *
 * @since   1.5
 */
public static function help($ref, $com = false, $override = null, $component = null)
{
    // Don't show a help button if neither $ref nor $override is given
    if (!$ref && !$override) {
        return;
    }
    $bar = Toolbar::getInstance('toolbar');
    // Add a help button.
    $bar->appendButton('Help', $ref, $com, $override, $component);
}