JSONP請求有限制: 第一,不能跳出兩層, 第二,不支援POST. 

往往解決跨域POST請求的方案是個"古老"方法, 請求同域下的iframe.

伺服器端: 

需要附加頭資訊:

1. header('Access-Control-Allow-Origin: *');  
2. header('Access-Control-Allow-Methods: POST');  
3. header('Access-Control-Max-Age: 1000');  

1. <script type='text/javascript'>document.domain=
   'xxx.com';Callback({"ret":0,"error":"xxx","data":null});</script>  

前端:

1. <section>  
2.     <form name="data_upload" action="http://request.com" method="post" target="upload_frame" onsubmit="return initUpload(this)" enctype="multipart/form-data"
   >  
3.        ......  
4.     <iframe src="" id="upload_frame" name="upload_frame" style="display: none"></iframe>  
5. </section>  

1. <script>  
2. function initUpload(formEle) {  
3.    ....  
4.    document.domain='xxx.com';  
5.    document.forms['data_upload'].submit();  
6. }  
7. </script>