fetch加上headers就跨域，去掉簽名又不正確，有人遇到過這個(gè)問題嗎？好像headers里邊加什么都加不進(jìn)去一樣 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