Nginx跨域设置Access-Control-Allow-Origin无效的解决办法

add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Credentials' 'true';add_header 'Access-Control-Allow-Methods' 'GET,POST';

if ($request_method = 'OPTIONS') {        add_header 'Access-Control-Allow-Origin' '*';        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';        add_header 'Access-Control-Max-Age' 1728000;        add_header 'Content-Type' 'text/plain charset=UTF-8';        add_header 'Content-Length' 0;        return 204;       }       if ($request_method = 'POST') {        add_header 'Access-Control-Allow-Origin' '*';        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';       }       if ($request_method = 'GET') {        add_header 'Access-Control-Allow-Origin' '*';        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';       }