Very handy function to avoid overflow on pages that are not to be scrolled

scrollon-off.js

function reloadScrollBars() {
    document.documentElement.style.overflow = 'auto';  // firefox, chrome
    document.body.scroll = "yes"; // ie only
}

function unloadScrollBars() {
    document.documentElement.style.overflow = 'hidden';  // firefox, chrome
    document.body.scroll = "no"; // ie only
}