var imageNumber = 0;
var fadein = true;
var topimage = false;

function startExchange() {
	window.onload = function() {
		topimage = document.getElementById('topimage');
		fadeTimout();
	}
}
function fadeTimout() {
	if (fadein) {
		if (imageNumber > topimages.length - 1) {
			imageNumber = 0;
		}
		topimage.src = topimages[imageNumber];
		fadeTopImageIn(0);
		imageNumber++;
	}
	else {
		fadeTopImageOut(100);
	}
}
function fadeTopImageIn(step) {
	var newStep = step + 1;
	
	if (document.all) {
		topimage.filters.item('DXImageTransform.Microsoft.Alpha').opacity = newStep;
	}
	else if (topimage.style.MozOpacity) {
		topimage.style.MozOpacity = newStep / 100;
	}
	else {
		topimage.style.opacity = newStep / 100;	
	}

	if (newStep < 100) {
		setTimeout(function() {
			fadeTopImageIn(newStep);
		},10);
	}
	else {
		fadein = false;
		setTimeout(function() {
			fadeTimout()
		},3000);
	}
}
function fadeTopImageOut(step) {
	var newStep = step - 1;
	
	if (document.all) {
		topimage.filters.item('DXImageTransform.Microsoft.Alpha').opacity = newStep;
	}
	else if (topimage.style.MozOpacity) {
		topimage.style.MozOpacity = newStep / 100;
	}
	else {
		topimage.style.opacity = newStep / 100;	
	}

	if (newStep > 0) {
		setTimeout(function() {
			fadeTopImageOut(newStep);
		},10);
	}
	else {
		fadein = true;
		fadeTimout()
	}
}