跨源ajax“ POST”请求失败

我有一个运行在localhost：8080上的webservice（REST），要使用以下jquery代码来调用该webservice：

jQuery.ajax({
        type: "POST",
        url: "http://localhost:8080/user/register",
        data: '{"name": "' + name + '","email": "' + email + '","password": "' + password + '"}',
         beforeSend: function(x) {
              if(x && x.overrideMimeType) {
               x.overrideMimeType(jsonMimeType);
              }
             },
        dataType:"jsonp",
        Accept : "application/json",
        contentType: "application/json",
        success: registerUser_success_callback,
        error: registerUser_error_callback
    });

当我尝试从相同的域（即localhost：8080）调用此javascript时，它就像一个吊饰一样工作！这是相同的屏幕截图：

但是，当我尝试从其他域（即localhost：80）访问相同文件时，它失败了，令人惊讶的是，它发出了GET消息，而不是POST消息，而且我还在服务器的日志文件中得到了一条日志，说GET REST资源不支持该方法。这是相同的屏幕：

From what I have read on internet(especially here, great article!), cross domain request should first send out an OPTIONS request(which is cached for later usage.) What is going wrong in my case?

I have tried calling the rest service with same parameters using FireFox's plugin RESTClient, I was able call the rest service(POST method) successfully, so this mostly is the issue with ajax part.

Help me resolve this cors hell! and do lemme know if I need to share any more details on this.

PS: After @A. Wolff Suggested, I changed the data tyoe from jsonp to json, now my browser sends out OPTIONS, but after that it doesn't send the actual POST request!!!