var items = 4;
var currentTop = 0;
var blockAnim = false;

function slideTo(num) {
	if (num != currentTop && !blockAnim) {
		blockAnim = true;
		
		var onTop = $('#adv-'+currentTop);
		var newTop = $('#adv-'+num);
		
		currentTop = num;
		newTop.css('z-index',10);
		
		onTop.fadeOut('slow', function(){
			newTop.css('z-index', 20);
			onTop.css('z-index', 5).fadeIn();
			
			blockAnim = false;
		});
		return true;
	}
	return false;
}

var sliderInterval;

function prepareNewLoop() {
	if (sliderInterval) {
		clearInterval(sliderInterval);
	}
	
	sliderInterval = setInterval(function(){
			slideTo((currentTop+1) % items);
		}, 5000);
}

$(document).ready(function() {
	prepareNewLoop();
});