如何将Jsoup connect对象代码转换为XMLHttpRequest对象javascript？

我刚开始学习AJAX。我的问题是：如何使用Javascript而不是Java连接到网站？在Java中，可以使用JSoup库和以下代码

Response res = Jsoup.connect(EDLINE_URL + "/InterstitialLogin.page").timeout(0).userAgent("Chrome/12.0.742.122").execute();

    Map<String, String> preLogCookies = res.cookies();
    System.out.println("Pre Login Cookies: " + preLogCookies);

    res = Jsoup.connect(EDLINE_URL + "/post/InterstitialLogin.page")
            .data("TCNK", "authenticationEntryComponent", 
                    "submitEvent", "1",
                    "guestLoginEvent", "",
                    "enterClicked", "false",
                    "bscf", "",
                    "bscv", "",
                    "targetEntid", "",
                    "ajaxSupported", "yes",
                    "screenName", username,
                    "kclq", password)
                    .cookies(preLogCookies)
                    .userAgent("Chrome/12.0.742.122")
                    .method(Method.POST)
                    .timeout(0)
                    .execute();

    loginCookies = res.cookies();
    loginCookies.putAll(preLogCookies);
    System.out.println("Login Cookies: " + loginCookies);

    System.out.println("Connected to: " + res.url());
    if (res.url().toString().contains("Notification.page")) {
        System.out.println("Username and Password Incorrect");
        System.exit(1);
    }

    return res;
}

这段代码是“不相关”的，是一个网站上的示例…但在理解我试图做的事情时可能会证明是有价值的…我不知道发生了什么，也不知道如何修改它。任何帮助都太好了

可能的重复可能的重复

var clientId = "MyApp";
var clientSecret = "MySecret";

var authorizationBasic = $.base64.btoa(clientId + ':' + clientSecret);

var request = new XMLHttpRequest();
request.open('POST', oAuth.AuthorizationServer, true);
request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
request.setRequestHeader('Authorization', 'Basic ' + authorizationBasic);
request.setRequestHeader('Accept', 'application/json');
request.send("username=John&password=Smith&grant_type=password");

request.onreadystatechange = function () {
    if (request.readyState == 4) {
    alert(request.responseText);
    }
};