function mouseScroll(delta,step) {
if (delta < 0) {
window.scrollBy(step,0);
} else {
window.scrollBy(-step,0);
}
}


function mouseWheel(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) {
mouseScroll(delta,150);
if (event.preventDefault) event.preventDefault();
event.returnValue = false;
}
}
if (window.addEventListener) {
window.addEventListener('DOMMouseScroll',mouseWheel,false);
}
window.onmousewheel = document.onmousewheel = mouseWheel;