问jQuery -尝试分析XML时，未捕获错误:无效的XML：[object Document]

EN

$.ajax({
    type: "GET",
    url: "xml/photobank.xml",
    dataType: "xml",
    success: function(xml){
        xmlParser(xml, "Charlie");
    }
});

function xmlParser(xml, landOwner) {

    //Initial photos do not load if following line is used.
    //xml = $.parseXML(xml);

    $('#photo_container').empty();
    console.log('1');
    $(xml).find('Landowner').each(function(){
        console.log('2');
        var landownerName = $(this).attr('Name');
        if (landownerName === landOwner) {
            $(this).find('Photo').each(function(){
                $("#photo_container").append('<div class="photo ' + $(this).find("Category").text().toLowerCase() + '"><p>' + $(this).find("Animal").text() + '</p>'+ '<img class="photobank" src="images/' + $(this).find("Image").text() + '" />' + '</div>');
            })
        }
    });
}

$('#btn_arnoldo').click(function(){
    xmlParser(xml, "Arnoldo");
});

$('#btn_arnoldo').click(function(){
    $.ajax({
        type: "GET",
        url: "xml/photobank.xml",
        dataType: "xml",
        success: function(xml){
            xmlParser(xml, "Arnoldo");
        }
    });
});