/**
 * Scroll div with buttons
 */
var autoscrollTimeout = null;
var interval = 25;
var step = 0;

function scrollUp() {
	var layer = document.getElementById("middle");
	layer.scrollTop -= 10;
	autoscrollTimeout = setTimeout("scrollUp()", interval);
	if(interval > 0 && step == 3) {
		interval -= 1;
		step = 0;
	} else {
		step++;
	}
}

function scrollDown() {
	var layer = document.getElementById("middle");
	layer.scrollTop += 10;
	autoscrollTimeout = setTimeout("scrollDown()", interval);
	if(interval > 0 && step == 3) {
		interval -= 1;
		step = 0;
	} else {
		step++;
	}
}

function stopScroll() {
	clearTimeout(autoscrollTimeout);
	autoscrollTimeout = null;
	interval = 25;
	step = 0;
}

function resetScroll() {
	var layer = document.getElementById("middle");
	layer.scrollTop = 0;
}

/**
 * Scroll div with mouse wheel
 */
function wheelTekst(event){
	var delta = 0;
	if (!event) event = window.event;
	if (event.wheelDelta) {
		delta = event.wheelDelta/120; 
		if (window.opera) delta = -delta;
	} else if (event.detail) {
		delta = -event.detail/3;
	}
	if (delta)
		handleScroll(delta);
        if (event.preventDefault)
                event.preventDefault();
        event.returnValue = false;
}

function handleScroll(delta) {
	var layer = document.getElementById("middle");
	layer.scrollTop -= delta*30;
}

if(document.getElementById("middle")) {
	var layer = document.getElementById("middle");
	/* Initialization code. */
	if (layer.addEventListener)
		layer.addEventListener('DOMMouseScroll', wheelTekst, false);
	layer.onmousewheel = wheelTekst;
}