function addClass($className)
{
if (!is_array($className)) {
$className = array($className);
}
$class = $this->class;
foreach ($className as $c) {
if (!(preg_match('`\\b' . preg_quote($c) . '\\b`si', $class) > 0)) {
$class .= ' ' . $c;
}
}
$this->class = trim($class);
}