javascript - IE 上的某些 AJAX 请求中的访问被拒绝？

Question

这是我试图触发的两个请求

$.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”错误的在线解决方案， 即我应该通过添加修改代码：

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,

这样最终的代码就在这两个链接中：

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

您可以在 IE 上尝试这两种方法，您会发现一个可以工作，另一个不能！

问题是：为什么一个请求返回成功而另一个仍然有访问被拒绝的问题并且失败了？！