关于withCredentials的跨域问题报错截图：原因：后端的Access-Control-Allow-Orig

报错截图：

跨域问题.png

Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'. Origin 'XXX' is therefore not allowed access. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute.

原因：

后端的Access-Control-Allow-Origin设置的是*，但是前端却设置了withCredentials：true来用于传递cookie信息

解决方法：

1.前端放弃传递cookie信息，withCredentials设置为false,

2.后端要设置Access-Control-Allow-Origin为前端的源地址，例如http://localhost:8080，不能是*，而且还要设置header(‘Access-Control-Allow-Credentials: true’);