微信公眾號OAuth2用戶授權報錯提示跨域

重定向到微信授權頁面時調試發現Status Code：301 Moved Permanently並且報錯提示跨域：

XMLHttpRequest cannot load
https://open.weixin.qq.com/connect/oauth2/authorize...#wechat_redirect. Redirect
from 'https://open.weixin.qq.com/connect/oauth2/authorize...#wechat_redirect' to
'https://open.weixin.qq.com/connect/oauth2/authorize...#wechat_redirect' has been
blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the
requested resource. Origin 'null' is therefore not allowed access.

在調試界面發現Headers里面出現了兩次重定向，所以才導致了這個問題。

解決方法是在微信提供的授權頁面鏈接中添加connect_redirect=1：

https://open.weixin.qq.com/connect/oauth2/authorize?appid=APPID&redirect_uri=REDIR
ECT_URI&response_type=code&scope=SCOPE&state=STATE&connect_redirect=1#wechat_redirect

再請求時Status Code：200 OK

原文地址：https://www.jianshu.com/p/8feea4d8e1c0