if ($chk($('banner'))){
	var count = $('banner').getElements('.block').length;
	$('banner').getElements('.block').each( function(el){
		el.addClass('hidden');
	});
	
	var i = 0;
	while (i < 3){
		var random = $random(0, count-1);
		var el = $('banner').getElements('.block')[random];
		if (el.hasClass('hidden')){
			el.removeClass('hidden');
			i++;
		}
	}
}