ipad safari: disable scrolling, and bounce effect?

You can use this jQuery code snippet to do this:

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

This will block the vertical scrolling and also any bounce back effect occurring on your pages.

You can also change the position of the body/html to fixed:

body,
html {
  position: fixed;
}

To prevent scrolling on modern mobile browsers you need to add the passive: false. I had been pulling my hair out getting this to work until I found this solution. I have only found this mentioned in one other place on the internet.

function preventDefault(e){
    e.preventDefault();
}

function disableScroll(){
    document.body.addEventListener('touchmove', preventDefault, { passive: false });
}
function enableScroll(){
    document.body.removeEventListener('touchmove', preventDefault);
}

This answer is no longer applicable, unless you are developing for a very old iOS device... Please see other solutions

2011 answer: For a web/html app running inside iOS Safari you want something like

document.ontouchmove = function(event){
    event.preventDefault();
}

For iOS 5 you may want to take the following into account: document.ontouchmove and scrolling on iOS 5

Update September 2014: A more thorough approach can be found here: https://github.com/luster-io/prevent-overscroll. For that and a whole lot of useful webapp advice, see http://www.luster.io/blog/9-29-14-mobile-web-checklist.html

Update March 2016: That last link is no longer active - see https://web.archive.org/web/20151103001838/http://www.luster.io/blog/9-29-14-mobile-web-checklist.html for the archived version instead. Thanks @falsarella for pointing that out.