function changeBanner(conf){
	if(banners>0){
		var nextBanner;
		if(conf=="prev"){
			nextBanner = currentBanner-1;
		}
		if(conf=="next"){
			nextBanner = currentBanner+1;
		}
		if(!isNaN(conf)){
			nextBanner = conf;
		}
		if(nextBanner>=1 && nextBanner<=banners){
			currentBanner = currentBanner - 1;
			nextBanner = nextBanner - 1;
			document.getElementById("image_" + currentBanner).style.display = "none";

			document.getElementById("image_"+ nextBanner).style.display = "block";


			currentBanner = nextBanner+1;
			
			}
		}else{
			changeBanner(1);
		}
	}