jQuery simplemodal disable scrolling

Question

I have more than 2000 pixels scrolling content on a page.

If the user clicks a div a scrolling content pops up in a simplemodal window. Now my client wants to make the original page non-scrollable while the modal window is up. (Of course the modal should be still scrollable.)

Is it even possible?

Edit: I have tried your suggestions. Basically it works, but the problem is a little bit complicated:

$(".foReadMoreLink a").click(function(){
    if ($('#modalBox').length == 0)
    $('body').append('<div style="display:none" id="modalBox"></div>')
    $('body').css({'overflow':'hidden'});
    $.post('jquery/loadarticle.php',{id:$(this).attr('id')},function(data){
        $('#modalBox').html(data).modal({overlayClose:'true'});
    })
    return false;
});

I use return false on the links so bots and users without JavaScript (yes, that's 2%) can open the articles. With the code above it works as expected, but after closing the modal I have to have back the scrollbar but this code won't work:

$(".foReadMoreLink a").click(function(){
    if ($('#modalBox').length == 0)
    $('body').append('<div style="display:none" id="modalBox"></div>')
    $('body').css({'overflow':'hidden'});
    $.post('jquery/loadarticle.php',{id:$(this).attr('id')},function(data){
        $('#modalBox').html(data).modal({onClose:function(){$('body').css({'overflow':'auto'})},overlayClose:'true'});
    })
    return false;
});

Answer 1

In your script to open your modal:

$("html,body").css("overflow","hidden");

And on close:

$("html,body").css("overflow","auto");

(HTML and body are required as the scroll bars are attached to different parts of the browser depending on which you are using)

Answer 2

Turning the scrollbars on and off will cause the content to shift and the overlay will no longer cover the whole window. Here's how to fix it.

var oldBodyMarginRight = $("body").css("margin-right");
$.modal(iframe, {
    onShow: function () {
        // Turn off scroll bars to prevent the scroll wheel from affecting the main page.  Make sure turning off the scrollbars doesn't shift the position of the content.
        // This solution works Chrome 12, Firefox 4, IE 7/8/9, and Safari 5.
        // It turns off the scroll bars, but doesn't prevent the scrolling, in Opera 11 and Safari 5.
        var body = $("body");
        var html = $("html");
        var oldBodyOuterWidth = body.outerWidth(true);
        var oldScrollTop = html.scrollTop();
        var newBodyOuterWidth;
        $("html").css("overflow-y", "hidden");
        newBodyOuterWidth = $("body").outerWidth(true);
        body.css("margin-right", (newBodyOuterWidth - oldBodyOuterWidth + parseInt(oldBodyMarginRight)) + "px");
        html.scrollTop(oldScrollTop); // necessary for Firefox
        $("#simplemodal-overlay").css("width", newBodyOuterWidth + "px")
    },
    onClose: function () {
        var html = $("html");
        var oldScrollTop = html.scrollTop(); // necessary for Firefox.
        html.css("overflow-y", "").scrollTop(oldScrollTop);
        $("body").css("margin-right", oldBodyMarginRight);
        $.modal.close();
    }
});