//Written by Nathan Faubion: http://n-son.com
//Use this or edit how you want, just give me
//some credit!

function jsScroller (o, w, h) {
	var self = this;
	attachWheelEvent(o, handleScroll);
	
	//Private methods
	this._setPos = function (x, y) {
		if (x < this.viewableWidth - this.totalWidth) 
			x = this.viewableWidth - this.totalWidth;
		if (x > 0) x = 0;
		if (y < this.viewableHeight - this.totalHeight) 
			y = this.viewableHeight - this.totalHeight;
		if (y > 0) y = 0;
		this._x = x;
		this._y = y;
		with (o.style) {
			left = this._x +"px";
			top  = this._y +"px";
		}
	};
	
	//Public Methods
	this.reset = function () {
		this.content = o;
		this.totalHeight = o.offsetHeight;
		this.totalWidth	 = o.offsetWidth;
		this._x = 0;
		this._y = 0;
		with (o.style) {
			left = "0px";
			top  = "0px";
		}
	};
	this.scrollBy = function (x, y) {
		this._setPos(this._x + x, this._y + y);
	};
	this.scrollTo = function (x, y) {
		this._setPos(-x, -y);
	};
	this.stopScroll = function () {
		if (this.scrollTimer) window.clearInterval(this.scrollTimer);
	};
	this.startScroll = function (x, y) {
		this.stopScroll();
		this.scrollTimer = window.setInterval(
			function(){ self.scrollBy(x, y); }, 40
		);
	};
	this.swapContent = function (c, w, h) {
		o = c;
		var list = o.getElementsByTagName("div");
		for (var i = 0; i < list.length; i++) {
			if (list[i].className.indexOf("scroller_container") > -1) {
				o = list[i];
			}
		}
		if (w) this.viewableWidth  = w;
		if (h) this.viewableHeight = h;
		this.reset();
	};
	
	//variables
	this.content = o;
	this.viewableWidth  = w;
	this.viewableHeight = h;
	this.totalWidth	 = o.offsetWidth;
	this.totalHeight = o.offsetHeight;
	this.scrollTimer = null;
	this.reset();
};

function attachWheelEvent(element, handler) {

	var mousewheelevt = (/Firefox/i.test(navigator.userAgent))? "DOMMouseScroll" : "mousewheel";

	if (element.attachEvent)
		element.attachEvent("on" + mousewheelevt, handler);
	else if (element.addEventListener)
		element.addEventListener(mousewheelevt, handler, false);

};

function handleScroll(e){

	var scrollStep = 30;

	var evt = window.event || e;
    var delta = evt.detail ? evt.detail*(-120) : evt.wheelDelta;

    if (evt.preventDefault) 
        evt.preventDefault()

	if (delta > 0)
		scroller.scrollBy(0, scrollStep);
	else if (delta < 0)
		scroller.scrollBy(0, -1 * scrollStep);
	
	return false;

};