var currentSlide  = 0;
var numSlides     = 4;
var newId         = "";
var currentId     = "";
var loadingTime   = 500;
var slideInterval = 5500;
var timerID       = 0;

function setUp()
{
	for (i=1;i<=numSlides;i++)
		document.getElementById("slide_"+i).style.visibility = "hidden";

	timerID = setTimeout("startSlideShow()", loadingTime);
}

function startSlideShow()
{
	if(timerID) {
		clearTimeout(timerID);
		timerID  = 0;
	}

	document.getElementById("slide-wrapper").style.display = "inline";
	switchSlide(1);
	timerID = setTimeout("nextSlide()", slideInterval);	
}

function nextSlide()
{
	if(timerID) {
		clearTimeout(timerID);
		timerID  = 0;
	}
	switchSlide(1);
	timerID = setTimeout("nextSlide()", slideInterval);	
}

function switchSlide(sDir) {
	newSlide = currentSlide + sDir;
	if (!newSlide)
		newSlide=numSlides;
	if (newSlide > numSlides)
		newSlide=1;
	
	newId     = "slide_"+newSlide;
	currentId = "slide_"+currentSlide;
	
	document.getElementById(newId).style.visibility = "visible";

	if (currentSlide != 0)
		document.getElementById(currentId).style.visibility = "hidden";
	else
		document.getElementById("slide-loading").style.display = "none";

	currentSlide = newSlide;
}

addLoadEvent(setUp);