Ajax Jquery w/ Error handling

// error handling
$.ajaxSetup({"error":function(XMLHttpRequest,textStatus, errorThrown) {
    alert(textStatus);
    alert(errorThrown);
    alert(XMLHttpRequest.responseText);
}});

// ajax request using Jquery with POST method, data and function to load when success.
$.ajax({
    type: 'POST',
    url: "data.php",
    data: {
        marker: markerData
        },
    success: function(data){
        loadMarkers();
        }
    });