public function setClasses( $classes )
	{
		$this->attributes['class']	= array();
		if( is_string( $classes ) )
			$classes	= explode( " ", $classes );
		if( !is_array( $classes ) && !( $classes instanceof ArrayIterator ) )
			throw new InvalidArgumentException( 'Class attribute must be string, array or iterator' );
		foreach( $classes as $class )
			$this->addClass( $class );
	}