预检标题响应问题

Question

我正在尝试使用XMLHttpRequest（）发出CORS请求。我在请求期间也在标题中进行了一些更改。服务器正在发送200 OK响应，但我在浏览器控制台中看到了预检响应错误：

客户端请求代码：

{
    "search_metadata" =     {
        "completed_in" = "0.05";
        count = 15;
        "max_id" = 680240431771156480;
        "max_id_str" = 680240431771156480;
        "next_results" = "?max_id=680240407322689535&q=%23ChristmasEve&include_entities=1";
        query = "%23ChristmasEve";
        "refresh_url" = "?since_id=680240431771156480&q=%23ChristmasEve&include_entities=1";
        "since_id" = 0;
        "since_id_str" = 0;
    };
    statuses =     (
                {
            contributors = "<null>";
            coordinates = "<null>";
            "created_at" = "Fri Dec 25 04:15:31 +0000 2015";
            entities =             {
                hashtags =                 (
                                        {
                        indices =                         (
                            0,
                            13
                        );
                        text = ChristmasEve;
                    },
                                        {

服务器端响应：

    var method = "POST";
    var tempURL = "http://127.0.0.1:8000/myFunc/";
    var body = {"key": "value"};

    var xhr = new XMLHttpRequest();
    xhr.open(method, tempURL, true);
    xhr.setRequestHeader('Access-Control-Allow-Origin', '*');
    xhr.setRequestHeader('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
    xhr.setRequestHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content-Length, X-Requested-With');
    xhr.send(body);

    if (!xhr) {
        alert('CORS not supported');
        return;
    }

    // Response handlers.
    xhr.onload = function() {
        alert("Data: " + xhr.responseText);
    };

    xhr.onerror = function() {
        alert('Oops, there was an error making the request.');
    };

错误（在浏览器控制台中）：

[25/Dec/2015 05:18:43] "OPTIONS /myFunc/ HTTP/1.1" 200 0

有人可以建议导致此问题的原因吗？需要做哪些更改以及在哪里（客户端/服务器端）？

谢谢，