var fadeForeground = document.getElementById("header-fade");
var fadeBackground = document.getElementById("header");

var fadeTimeout = 4000;
var nextFadeN = 2;



function setOpacity(object,opacityPct) {
	// IE.
	object.style.filter = 'alpha(opacity=' + opacityPct + ')';
	// Old mozilla and firefox
	object.style.MozOpacity = opacityPct/100;
	// Everything else.
	object.style.opacity = opacityPct/100;
}

function changeOpacity(id,msDuration,msStart,fromO,toO) {
	
	var element=document.getElementById(id);
	var opacity = element.style.opacity * 100;
	var msNow = (new Date()).getTime();
	opacity = fromO + (toO - fromO) * (msNow - msStart) / msDuration;
	if (opacity<0) 
		setOpacity(element,0)
	else if (opacity>100) {
		setOpacity(element,100)
		
		prepareNextFade();
	}
	else
	{
		setOpacity(element,opacity);
		element.timer = window.setTimeout("changeOpacity('" + id + "'," + msDuration + "," + msStart + "," + fromO + "," + toO + ")",10);
	}
}


function fadeInImage() {
	
	if (fadeForeground.timer) window.clearTimeout(fadeForeground.timer);	
	var startMS = (new Date()).getTime();
	fadeForeground.timer = window.setTimeout("changeOpacity('header-fade',1000," + startMS + ",0,100)", 1);
}


function prepareFadeImage(newImage) {
	
	fadeBackground.style.backgroundImage = fadeForeground.style.backgroundImage;
	fadeBackground.style.backgroundRepeat = 'no-repeat';
	
	setOpacity(fadeForeground,0);
	
	fadeForeground.style.backgroundImage = 'url(' + newImage + ')';
	fadeForeground.style.backgroundRepeat = 'no-repeat';
	
	
	window.setTimeout("fadeInImage()", fadeTimeout);
}



function prepareNextFade() {
	
	prepareFadeImage("/website/gns/template/styles/images/header/" + nextFadeN + ".jpg");
	
	nextFadeN++;
	if (nextFadeN > 9) nextFadeN = 1;
}


window.setTimeout("prepareNextFade()", 1000);