var uptimer = false;
var downtimer = false;
var nachoben = '<ul class="subnavigation"><a onMouseOut="MM_swapImgRestore();" onMouseOver="MM_swapImage(\'oben\',\'\',\'/bilder/pfeil-oben-aktiv.png\',1);"  onmousedown="move_up();" onmouseup="deleteTimer();"><li><img name="oben" border="0" src="/bilder/pfeil-oben.png" width="100px" height="18px"></li></a></ul>';
var nachunten = '<ul class="subnavigation"><a onMouseOut="MM_swapImgRestore();" onMouseOver="MM_swapImage(\'unten\',\'\',\'/bilder/pfeil-unten-aktiv.png\',1);" onmousedown="move_down();" onmouseup="deleteTimer();"><li><img name="unten" border="0" src="/bilder/pfeil-unten.png" width="100px" height="22px"></li></a></ul>';
var nachoben_inaktiv = '<ul class="subnavigation"><li><img name="oben" border="0" src="/bilder/pfeil-oben-inaktiv.png" width="100px" height="18px"></li></ul>';
var nachunten_inaktiv = '<ul class="subnavigation"><li><img name="unten" border="0" src="/bilder/pfeil-unten-inaktiv.png" width="100px" height="22px"></li></ul>';
var aktScroll = false;

function resizeScroller() {
	var content = document.getElementById("scroller");
	//
	content.scrollTop = 0;
	var aktHeight = document.documentElement.clientHeight - 150;
	if (aktHeight > content.scrollHeight) {
		aktHeight = "auto";
		document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben_inaktiv;
		document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten_inaktiv;
	}
	else if (aktHeight < 100) {
		aktHeight = 100+"px";
		if (content.scrollTop > 0) {
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben;
		}
		else {
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben_inaktiv;
		}
		document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten;
	}
	else {
		aktHeight = aktHeight + "px";
		if (content.scrollTop > 0) {
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben;
		}
		else {
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben_inaktiv;
		}
		document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten;
	}
    document.getElementById("scroller").style.height = aktHeight;
}
window.onresize = resizeScroller;


function handle(delta) {
	var s = delta + ": ";
	if (delta < 0)
		move_down(delta);
	else
		move_up(delta);
}

function wheel(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)
		handle(delta);
        if (event.preventDefault)
               event.preventDefault();
        event.returnValue = false;
}

/* Initialization code. */
function startScrolling(){
	if (document.getElementById("scroller").addEventListener) 
		document.getElementById("scroller").addEventListener('DOMMouseScroll', wheel, false);
	document.getElementById("scroller").onmousewheel = document.getElementById("scroller").onmousewheel = wheel;
}

function deleteTimer() {
	clearTimeout(downtimer);
	clearTimeout(uptimer);
}

function move_up(delta){
	var content = document.getElementById("scroller");
	if (delta) {
		content.scrollTop -= delta * 5;
	}
	else {
		content.scrollTop -= 2;
	}
	if (content.scrollTop > 0) {
		document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben;
		document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten;
		if (!delta) {
			uptimer = setTimeout("move_up()", 20);
		}
	}
	else {
		deleteTimer();
		document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben_inaktiv;
		document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten;
	}
}

function move_down(delta) {
	var content = document.getElementById("scroller");
	aktScroll = content.scrollTop;
	if (delta) {
		delta = Math.abs(delta* 5);
		content.scrollTop += delta;
	}
	else {
		content.scrollTop += 2;
	}
	aktScrollint = content.scrollTop;
	if (content.scrollTop > 0) {
		if (aktScrollint > aktScroll) {
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben;
			document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten;
			if (!delta) {
				downtimer = setTimeout("move_down()", 20);
			}		
		}
		else {
			deleteTimer();
			document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben;
			document.getElementById("subnavigation-scroll-unten").innerHTML = nachunten_inaktiv;
		}
	}
	else {
		deleteTimer();
		document.getElementById("subnavigation-scroll-oben").innerHTML = nachoben_inaktiv;
	}
}