var currentBanner;
var _alpha = 1;
var last = 1;
var T = 1;
var K = 0.01;
var MAX = 5 * 1000;
function $$(id) {
	return document.getElementById(id);
}

make_banner();
function make_banner() {
	setTimeout("change_banner()", MAX);
}
function change_banner() {
	currentBanner = $$("promobanner" + last);
	fade();
}
function show_next_banner() {
	last++;
	last = last == 4 ? 1 : last;
	currentBanner = $$("promobanner" + last);
	appear();	
}
function fade() {
	if (currentBanner) {
		currentBanner.style.opacity = _alpha;	
		currentBanner.style.filter = "alpha(opacity="+(_alpha*100)+")";
		if (_alpha > 0) {
			_alpha -= K;
			setTimeout("fade()", T);
		} else {
			currentBanner.style.display = "none";
			show_next_banner();
		}
	}
}
function appear() {
	if (currentBanner) {
		currentBanner.style.display = "";
		currentBanner.style.opacity = _alpha;	
		currentBanner.style.filter = "alpha(opacity="+(_alpha*100)+")";		
		if (_alpha < 1) {
			_alpha += K;
			setTimeout("appear()", T);
		} else {
			make_banner();
		}
	}
}