jquery infinite scroll

1$(window).scroll(function () {
2    // End of the document reached?
3    if ($(document).height() - $(this).height() == $(this).scrollTop()) {
4        $.ajax({
5            type: "POST",
6            url: "index.aspx/GetData",
7            contentType: "application/json; charset=utf-8",
8            data: '',
9            dataType: "json",
10            success: function (msg) {
11                if (msg.d) {
12                    $(".container").append(msg.d);
13                }
14            },
15            error: function (req, status, error) {
16                alert("Error try again");
17            }
18        });
19    }
20}); 
21