var int_interval = 32;

window.onscroll = function() {
	var topAmount = (window.pageYOffset ? window.pageYOffset : 0,document.documentElement ? document.documentElement.scrollTop : 0,document.body ? document.body.scrollTop : 0);
	document.getElementById("lbOverlay").style.top =  topAmount;
	document.getElementById("msg_container").style.top = topAmount+314;
}

function startFade() {
	fadeIn('lbOverlay', 0, 6);
	fadeIn('msg_container', 0, 10);
}
	
function closeAlert() {
	fadeOut('msg_container', 10, 0);
	fadeOut('lbOverlay', 6, 0);
}
	
function fadeIn(domId, int_start, int_finish) {
	obj = document.getElementById(domId);
	function f() {
		int_start++;
		setOpacity(domId, int_start);
		if (int_start <= int_finish) {
			setTimeout(f, int_interval);
			obj.style.visibility = "visible";
		}
	}
	setTimeout(f, int_interval);
}

function fadeOut(domId, int_start, int_finish) {
	obj = document.getElementById(domId);
	function f() {
		int_start--;
		setOpacity(domId, int_start);
		if (int_start > int_finish) {
			setTimeout(f, int_interval);
		} 
		if (int_start == 0) {
			obj.style.visibility = "hidden";
		}
	}
	setTimeout(f, int_interval);
}

function setOpacity(domId, val){
	obj = document.getElementById(domId);
	obj.style.MozOpacity = val;
	obj.style.opacity = val/10;
	obj.style.filter = 'alpha(opacity=' + val*10 + ')';
	//alert(obj.offsetHeight);
}