function preventDefault(e) {
e = e || window.event;
if (e.preventDefault)
e.preventDefault();
e.returnValue = false;
}
function preventDefaultForScrollKeys(e) {
if (keys[e.keyCode]) {
preventDefault(e);
return false;
}
}
function disableScroll() {
if (window.addEventListener) // older FF
window.addEventListener('DOMMouseScroll', preventDefault, false);
window.onwheel = preventDefault; // modern standard
window.onmousewheel = document.onmousewheel = preventDefault; // older browsers, IE
window.ontouchmove = preventDefault; // mobile
document.onkeydown = preventDefaultForScrollKeys;
}
function enableScroll() {
if (window.removeEventListener)
window.removeEventListener('DOMMouseScroll', preventDefault, false);
window.onmousewheel = document.onmousewheel = null;
window.onwheel = null;
window.ontouchmove = null;
document.onkeydown = null;
}