How to prevent document scrolling but allow scrolling inside div elements on websites for iOS and Android?

I created a website with jQueryMobile for iOS and Android.

I don't want the document itself to scroll. Instead, just an area (a <div> element) should be scrollable (via css property overflow-y:scroll).

So I disabled document scrolling via:

$(document).bind("touchstart", function(e){
    e.preventDefault();
});

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

But that will also disable scrolling for all other elements in the document, no matter if overflow:scroll is set or not.

How can I solve this?

Finally, I got it to work. Really simple:

var $layer = $("#layer");
$layer.bind('touchstart', function (ev) {
    var $this = $(this);
    var layer = $layer.get(0);

    if ($this.scrollTop() === 0) $this.scrollTop(1);
    var scrollTop = layer.scrollTop;
    var scrollHeight = layer.scrollHeight;
    var offsetHeight = layer.offsetHeight;
    var contentHeight = scrollHeight - offsetHeight;
    if (contentHeight == scrollTop) $this.scrollTop(scrollTop-1);
});