var k = 0.1, size = 200;
var activity = 0;
function calcOffsetX(el) {
	offset = el.offsetLeft;
	if (el.offsetParent) 
		offset += calcOffsetX(el.offsetParent)
	return offset;
}
function calcOffsetY(el) {
	offset = el.offsetTop;
	if (el.offsetParent) 
		offset += calcOffsetY(el.offsetParent)
	return offset;
}
function mouseMove(evt) {
	if (!evt) evt = event;
	if (activity) {
		el = document.getElementById("sliderdiv");
		x = evt.clientX;
		y = evt.clientY;
		x += document.body.scrollLeft;
		y += document.body.scrollTop;
		x -= calcOffsetX(el);
		y -= calcOffsetY(el);
		if ((x >= 8) && (x < size)) {
			slide(x-size);
			slideNumber = Math.round(x * (numberOfSlides-1) / size);
			if (lastSlide != slideNumber) {
				//window.status = x + ":" + y + "->" + slideNumber;
				textElement = document.getElementById("sliderText"+lastSlide);
				textElement.style.display = "none";
				lastSlide = slideNumber;
				textElement = document.getElementById("sliderText"+lastSlide);
				textElement.style.display = "block";
				// get element to set background to
				imageElement = document.getElementById("bgImage");
				// image name /pic/slider/image{lastSlide}.gif			
				imageElement.style.backgroundImage = "url(/pic/slider/image"+lastSlide+".jpg)";
			}
		}
	}
	return false;
}
function min(a,b) {
	return (a < b) ? a : b;
}
var lastSlide = 0;
var numberOfSlides = 0;
function slide(slider) {
	el = document.getElementById("slider");
	el.style.left = slider;
}
function mouseDown(evt)
{
	activity = 1;
	return false;
}
function mouseUp(evt)
{
	mouseMove(evt);
	activity = 0;
	return false;
}