jQuery .append不追加

Question

I'm trying to add posts as the user reaches the #marker-end in an HTML page using jQuery/LazyLoadXT:

This is the javascript:

$(document).ready(function () {
    $('#marker-end')
        .on('lazyshow', function () {
            $.ajax({
                url: '/get_content_item/',
                dataType: "html"
            })
            .success(function (responseText) { **note that I tried .done also**
                // add new elements
                $('#infinite').append(
                    $('<div>')
                        .append($.parseHTML(responseText))
                        .find('#infinite')
                        .children()
                );
                // process added elements
                $(window).lazyLoadXT();
                $('#marker-end').lazyLoadXT({visibleOnly: false, checkDuplicates: false});
                });
        })
        .lazyLoadXT({visibleOnly: false});
});

and there's this in my HTML page:

<div id="infinite"></div>
<div id="marker-end"></div>

The ajax call is working, and in Chrome developer tools I see a response from the server, so I know the problem is somewhere with the appended data not showing up with jQuery. The code is similar to the LazyLoadXT page, however I can't get it working.

Any help is greatly appreciated. Thanks! :)