function banner() {
	var timer = window.setInterval("changeBanner()", 10000);
}
function changeBanner() {
	var numBanners = document.getElementById('numBanners');
	var numOfBanners = numBanners.value;
	var currBanner = document.getElementById('currBanner');
	var currBannerNumber = currBanner.value;
	var nextBannerNumber = parseInt(currBannerNumber) + 1;
	var prevBannerNumber;
  	
	if (currBannerNumber >= (parseInt(numOfBanners) - 1)) {
		currBanner.value = 0;
	}
	else {
		currBanner.value = nextBannerNumber;
	}
	
	if (currBannerNumber == 0) {
		prevBannerNumber = parseInt(numOfBanners) - 1;
	}
	else {
		prevBannerNumber = parseInt(currBannerNumber) - 1;
	}
	
	var prevLayer = document.getElementById('banItem'+prevBannerNumber);
	prevLayer.style.visibility = 'hidden';
	prevLayer.style.display = 'none';
	var currLayer = document.getElementById('banItem'+currBannerNumber);
	currLayer.style.visibility = 'visible';
	currLayer.style.display = 'block';
}