jQuery跨域请求

我正在尝试获得跨域请求才能工作。相关代码如下：

var promise = $.ajax({
    type: 'GET',
    url: registerUrl,
    dataType: 'json',
    cache: false,
    crossDomain: true,
    xhrFields: { withCredentials: true },
    contentType: 'application/json'
});

我控制呼叫和接收服务器，这是我得到的响应：

原始请求（由Fiddler提供）：

OPTIONS http://localhost:5080/mportal/registerChat?gsid=abcde&ul=100,200&_=1405022169353 HTTP/1.1
Host: localhost:5080
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20100101 Firefox/29.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: http://localhost:53054
Access-Control-Request-Method: GET
Access-Control-Request-Headers: content-type
Connection: keep-alive

原始回应：

HTTP/1.1 200 OK
Date: Thu, 10 Jul 2014 19:56:11 GMT
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE
Content-Length: 0
Server: Jetty(8.1.4.v20120524)

现在，我的理解是，Allow-Origin: *对于此预检而言，Firefox / Chrome应该足以让请求继续进行。奇怪的是，IE不会对此请求进行预检，并且可以正常工作（尽管会发出警告，表明它未遵循CORS规范）。

我在这里想念什么吗？我尝试设置我能想到的ajax请求上的每个值，并且服务器看起来正在以对OPTIONS请求的适当响应进行响应。

来自firefox的特定错误消息：

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:5080/mportal/registerChat?gsid=abcde&ul=100,200&_=1405022169353. This can be fixed by moving the resource to the same domain or enabling CORS.

我究竟做错了什么？可以更改以解决此问题？

编辑：新的请求/响应字段：

OPTIONS http://localhost:5080/mportal/registerChat?gsid=abcde&ul=100,200&_=1405026511996 HTTP/1.1
Host: localhost:5080
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: http://localhost:53054
Access-Control-Request-Method: GET
Access-Control-Request-Headers: content-type
Connection: keep-alive

响应：

HTTP/1.1 200 OK
Date: Thu, 10 Jul 2014 21:08:38 GMT
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE
Access-Control-Allow-Headers: content-type
Access-Control-Allow-Credentials: true
Content-Length: 0
Server: Jetty(8.1.4.v20120524)

现在，提琴手还记录了实际的请求：

GET http://localhost:5080/mportal/registerChat?gsid=abcde&ul=100,200&_=1405026511996 HTTP/1.1
Host: localhost:5080
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/json
Referer: http://localhost:53054/
Origin: http://localhost:53054
Connection: keep-alive

以及响应：

HTTP/1.1 200 OK
Date: Thu, 10 Jul 2014 21:08:38 GMT
Content-Type: application/json;charset=ISO-8859-1
Content-Length: 175
Server: Jetty(8.1.4.v20120524)

{"status":true,"host":"<myServerName>","port":1935,"liveHost":"<myServerName>","livePort":5080,"gsid":"abcde","connCount":2,"maxConns":25000,"version":"1.0"}

但是，firefox似乎阻止了该请求，因此ajax调用总是命中我的失败处理程序。这似乎很奇怪...