在IE上的某些AJAX请求中拒绝访问？

Question

这是我要解雇的两个请求

$.ajax({
    url : "http://api.geonames.org/citiesJSON",
    type : 'POST',
    cache : false,
    dataType : 'json',
    data : {
        username: "demo", 
        north:10, 
        south: 10, 
        east:10, 
        west:10}
}).done(function(data) {
    alert("Success: " + JSON.stringify(data));
}).fail(function(a, b, c, d) {
    alert("Failure: " 
          + JSON.stringify(a) + " " 
          + JSON.stringify(b) + " " 
          + JSON.stringify(c) + " " 
          + JSON.stringify(d) );
});

和

$.ajax({
    url : "https://app.testafy.com/api/v0/user/login",
    type : 'POST',
    cache : false,
    dataType : 'json',
    data : {
        login_name: "abashir", 
        password: "P@ssw0rd"}
}).done(function(data) {
    alert("Success: " + JSON.stringify(data));
}).fail(function(a, b, c, d) {
    alert("Failure: " 
          + JSON.stringify(a) + " " 
          + JSON.stringify(b) + " " 
          + JSON.stringify(c) + " " 
          + JSON.stringify(d) );
});

由于IE中的跨域问题，我找到了"No Transport" error的在线解决方案，我应该通过添加以下内容来修改代码：

if (!jQuery.support.cors && window.XDomainRequest) {
    var httpRegEx = /^https?:\/\//i;
    var getOrPostRegEx = /^get|post$/i;
    var sameSchemeRegEx = new RegExp('^'+location.protocol, 'i');
    var xmlRegEx = /\/xml/i;

    // ajaxTransport exists in jQuery 1.5+
    jQuery.ajaxTransport('text html xml json', function(options, userOptions, jqXHR){
        // XDomainRequests must be: asynchronous, GET or POST methods, HTTP or HTTPS protocol, and same scheme as calling page
        if (options.crossDomain && options.async && getOrPostRegEx.test(options.type) && httpRegEx.test(userOptions.url) && sameSchemeRegEx.test(userOptions.url)) {
            var xdr = null;
            var userType = (userOptions.dataType||'').toLowerCase();
            return {
                send: function(headers, complete){
                    xdr = new XDomainRequest();
                    if (/^\d+$/.test(userOptions.timeout)) {
                        xdr.timeout = userOptions.timeout;
                    }
                    xdr.ontimeout = function(){
                        complete(500, 'timeout');
                    };
                    xdr.onload = function(){
                        var allResponseHeaders = 'Content-Length: ' + xdr.responseText.length + '\r\nContent-Type: ' + xdr.contentType;
                        var status = {
                            code: 200,
                            message: 'success'
                        };
                        var responses = {
                            text: xdr.responseText
                        };

                                try {
                                    if (userType === 'json') {
                                        try {
                                            responses.json = JSON.parse(xdr.responseText);
                                        } catch(e) {
                                            status.code = 500;
                                            status.message = 'parseerror';
                                            //throw 'Invalid JSON: ' + xdr.responseText;
                                        }
                                    } else if ((userType === 'xml') || ((userType !== 'text') && xmlRegEx.test(xdr.contentType))) {
                                        var doc = new ActiveXObject('Microsoft.XMLDOM');
                                        doc.async = false;
                                        try {
                                            doc.loadXML(xdr.responseText);
                                        } catch(e) {
                                            doc = undefined;
                                        }
                                        if (!doc || !doc.documentElement || doc.getElementsByTagName('parsererror').length) {
                                            status.code = 500;
                                            status.message = 'parseerror';
                                            throw 'Invalid XML: ' + xdr.responseText;
                                        }
                                        responses.xml = doc;
                                    }
                                } catch(parseMessage) {
                                    throw parseMessage;
                                } finally {
                                    complete(status.code, status.message, responses, allResponseHeaders);
                                }
                            };
                            xdr.onerror = function(){
                                complete(500, 'error', {
                                    text: xdr.responseText
                                });
                            };
                            xdr.open(options.type, options.url);
                            //xdr.send(userOptions.data);
                            xdr.send();
                        },
                        abort: function(){
                            if (xdr) {
                                xdr.abort();
                            }
                        }
                    };
                }
            });
};

jQuery.support.cors = true; 

并在ajax请求中添加以下属性

crossDomain: true,

这样最终的代码与这两个链接一样：

• http://jsfiddle.net/8vnxA/6/
• http://jsfiddle.net/bjW8t/4/

你可以在IE上试试这两个，你会发现一个正在工作而另一个没有！

问题是：为什么其中一个请求会返回成功而另一个请求仍然存在拒绝访问权限并且失败了？!!