You can cover-up the window with a scrollable div for preventing scrolling of the content on a page. And, by hiding and showing, you can lock/unlock your scroll.
Do something like this:
#scrollLock {
width: 100%;
height: 100%;
position: fixed;
overflow: scroll;
opacity: 0;
display:none
}
#scrollLock > div {
height: 99999px;
}
function scrollLock(){
$('#scrollLock').scrollTop('10000').show();
}
function scrollUnlock(){
$('#scrollLock').hide();
}