How to disable scrolling temporarily?

The scroll event cannot be canceled. But you can do it by canceling these interaction events:
Mouse & Touch scroll and Buttons associated with scrolling.

[Working demo]

// left: 37, up: 38, right: 39, down: 40,// spacebar: 32, pageup: 33, pagedown: 34, end: 35, home: 36var keys = {37: 1, 38: 1, 39: 1, 40: 1};function preventDefault(e) {  e.preventDefault();}function preventDefaultForScrollKeys(e) {  if (keys[e.keyCode]) {    preventDefault(e);    return false;  }}// modern Chrome requires { passive: false } when adding eventvar supportsPassive = false;try {  window.addEventListener("test", null, Object.defineProperty({}, 'passive', {    get: function () { supportsPassive = true; }   }));} catch(e) {}var wheelOpt = supportsPassive ? { passive: false } : false;var wheelEvent = 'onwheel' in document.createElement('div') ? 'wheel' : 'mousewheel';// call this to Disablefunction disableScroll() {  window.addEventListener('DOMMouseScroll', preventDefault, false); // older FF  window.addEventListener(wheelEvent, preventDefault, wheelOpt); // modern desktop  window.addEventListener('touchmove', preventDefault, wheelOpt); // mobile  window.addEventListener('keydown', preventDefaultForScrollKeys, false);}// call this to Enablefunction enableScroll() {  window.removeEventListener('DOMMouseScroll', preventDefault, false);  window.removeEventListener(wheelEvent, preventDefault, wheelOpt);   window.removeEventListener('touchmove', preventDefault, wheelOpt);  window.removeEventListener('keydown', preventDefaultForScrollKeys, false);}

UPDATE: fixed Chrome desktop and modern mobile browsers with passive listeners

Do it simply by adding a class to the body:

.stop-scrolling {  height: 100%;  overflow: hidden;}

Add the class then remove when you want to re-enable scrolling, tested in IE, FF, Safari and Chrome.

$('body').addClass('stop-scrolling')

For mobile devices, you'll need to handle the touchmove event:

$('body').bind('touchmove', function(e){e.preventDefault()})

And unbind to re-enable scrolling. Tested in iOS6 and Android 2.3.3

$('body').unbind('touchmove')

Here's a really basic way to do it:

window.onscroll = function () { window.scrollTo(0, 0); };

It's kind of jumpy in IE6.