public function addClass($class) {

		// classes array
		if (is_array($class)) {
			
			// adds all of them
			foreach ($class as $c) {
				if (!in_array($c, $this->class)) {
					$this->class[] = $c;
				}
			}
			
		// single class
		} else if (!in_array($class, $this->class)) {
			
			$this->class[] = $class;
			
		}

		return $this;

	}