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

function AttachWheelEvent(element)
{
    if (window.addEventListener)
        element.addEventListener('DOMMouseScroll', wheel, false);        
    
    element.onmousewheel = wheel;     
}