Variety of POST examples in JavaScript

PostExamples.js

function postMessageXhr() {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "", true);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.send(JSON.stringify({
        ApplicationName: "",
        ComputerName: "",
        OperatingSystem: "",
        UserName: "",
        LogLevel: "",
        Message: ""
    }));
}

function postMessageAjax() {

    $.ajaxSetup({
        crossDomain: true,
        xhrFields: {
            withCredentials: true
        },
    });

    $.ajax({
        url: '',
        data: JSON.stringify({
            ApplicationName: '',
            ComputerName: '',
            OperatingSystem: '',
            UserName: '',
            LogLevel: '',
           Message: ''
        }),
        dataType: "json",
        contentType: 'application/json',
        type: 'POST',
        error: function (xhr, status, error) {
            app.showNotification(_appName, error);
        }
    }).done(function (data) {
        app.showNotification(_appName, data);
    });
}

function postMessageJquery() {
    $.post("", {
        ApplicationName: '',
        ComputerName: '',
        OperatingSystem: '',
        UserName: '',
        LogLevel: '',
        Message: ''
    }).done(function (data) {
        app.showNotification(_appName, data);
    }).fail(function (xhr, status, error) {
        app.showNotification(_appName, xhr.statusText);
    });
}