jQuery UI dialog - Outer window scrolls while scrolling inside the dialog

Question

I'm using a jQuery UI dialog to show a popup containing a page. When I scroll inside the popup and if the scroll bars comes to the bottom, the parent page starts scrolling. How can I restrict the parent page from scrolling while scrolling inside the dialog?

I've created a modal dialog using the following code.

// Dialog
$('#dialog').dialog({
    autoOpen: false,
    width: 800,
    height: 550,
    minHeight: 500,
    maxHeight: 800,
    minWidth: 500,
    maxWidth: 900,
    modal: true,
    buttons: {
        "Cancel": function () {
            $(this).dialog("close");
        }
    }
});

$('#AddNewItems').click(function () {
    var currentURL = getURLOfCurrentPage();
    $('#dialog').dialog('open');
    $("#dialog").dialog("option", "width", 800);
    $("#dialog").dialog("option", "height", 550);
    $("#dialog").dialog( "option", "draggable", false );
    $("#dialog").dialog( "option", "modal", true );
    $("#dialog").dialog( "option", "resizable", false );
    $('#dialog').dialog("option", "title", 'My Title');
    $("#modalIframeId").attr("src", "http://myUrl");
    return false;
});

Answer 1

This is what I use:

$('#dialog').dialog({
    autoOpen: false,
    width: 800,
    height: 550,
    minHeight: 500,
    maxHeight: 800,
    minWidth: 500,
    maxWidth: 900,
    modal: true,
    buttons: {
        "Cancel": function () {
            $(this).dialog("close");
        }
    },
    open: function(){
        $("body").css("overflow", "hidden");
    },
    close: function(){
        $("body").css("overflow", "auto");
    }
});