/**
 * JS Scrolling

 */
 
var scrollHandler;

function ScrollHandler(handleWheel) {
	scrollHandler = this;
	this.handleWheel = handleWheel;
	
	if (window.addEventListener)
		/** DOMMouseScroll is for mozilla. */
		window.addEventListener('DOMMouseScroll', wheelHandler, false);

	/** IE/Opera. */
	window.onmousewheel = document.onmousewheel = wheelHandler;

	return this;
}


/**
 * Event handler for mouse wheel event.
 */
function wheelHandler(event) {
	var delta = 0;
	if (!event) /* For IE. */
		event = window.event;
	if (event.wheelDelta) { /* IE/Opera. */
		delta = event.wheelDelta/120;
		
	} else if (event.detail) { /** Mozilla case. */
	
		delta = -event.detail / 3;
	}
	
	if (delta != 0 && scrollHandler.handleWheel)
		scrollHandler.handleWheel(delta > 0 ? 1 : -1);

	
	if (event.preventDefault)
		event.preventDefault();
	event.returnValue = false;
}