fx.Background = Class.create();
		fx.Background.prototype = Object.extend(new fx.Base(), {
			initialize: function(el, options) {
				this.el = $(el);
				this.setOptions(options);
				this.now = 0;
			},
			increase: function() {
				this.el.style.marginLeft = this.now + "px";						
			},
			scroll: function(howMuch){
				this.clearTimer();

				// calculate the width of elements, including padding/border								
				var scroll_limit = this.el.offsetWidth - this.el.parentNode.offsetWidth;
				
				if (((this.now + howMuch) <= 0) && ((this.now + howMuch) >= -(Math.abs(howMuch) + scroll_limit))) {
					this.custom(this.now, this.now + howMuch);
				}
				
			}
		});

		window.onload = function() {			
			myNewEffect = new fx.Background('examplescrolling', {duration: 210});