function handle(delta) {
	return document.getElementById("jswheel").wheelUpdate(delta);
}

function wheel(event){
	var delta = 0;
	if (!event) event = window.event;
	if (event.wheelDelta) {
		delta = event.wheelDelta/120; 
	} else if (event.detail) {
		delta = -event.detail/3;
	}
	var allowWheel;
	if (delta) allowWheel = handle(delta);
	
	if (!allowWheel) {
        if (event.preventDefault) event.preventDefault();
        event.returnValue = false;
	}
}

if (window.addEventListener) window.addEventListener('DOMMouseScroll', wheel, false);
window.onmousewheel = document.onmousewheel = wheel;