Access to XMLHttpRequest at ‘http://localhost:9003。。。。/deletesubject1173935603251679233‘ from origin ‘http://localhost:9530‘ has been blocked by CORS policy: Response to preflight request doesn‘t pass access control check: No ‘Access-Control-Allow-Origin‘ header is present on the requested resource.
‘http://localhost:9003/deletesubject1173935603251679233‘路径上少了一个/，添加上就好了
原文：https://www.cnblogs.com/minmin123/p/11545083.html