fetch加上headers就跨域，去掉签名又不正确，有人遇到过这个问题吗？ 好像headers里边加什么都加不进去一样

 Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access.

[h5-render] unexpected error in _xhr for 'fetch' API