JavaScript: Listening all ajax events

ajax_events.js

!function ($) {
    var logEvent = function(event) {
        $('.notifier').append('<p>'+event+'</p>');
    }

    $(document).ajaxStart(onStart)
       .ajaxStop(onStop)
       .ajaxSend(onSend)
       .ajaxComplete(onComplete)
       .ajaxSuccess(onSuccess)
       .ajaxError(onError);

    // declare callback functions
    function onStart(event) {
        logEvent('Loading...');
    }

    function onStop(event) {
        // logEvent(event);
    }

    function onSend(event, xhr, settings) {
        logEvent('Iniciando.');
    }

    function onComplete(event, xhr, settings) {
        logEvent('Completed.');
    }

    function onSuccess(event, xhr, settings) {
        logEvent('Success!');
    }

    function onError(event, xhr, settings, err) {
        // logEvent(event, xhr, settings, err);
    }

    $.get(
        'http://127.0.0.1:8000/ajax_content.html',
        function(response) {
            $('.placeholder').html(response);
        },
        'html'
    );
}(window.jQuery);