本地localhost8081端口訪問(wèn)8080端口算跨域么，怎么配置nginx后訪問(wèn)報(bào)404

本地8081端口的html，ajax提交post請(qǐng)求到8080端口，然后nginx攔截demo開(kāi)頭的url，轉(zhuǎn)發(fā)到localhost8080，這樣有毛病嗎

server {

     listen       8081;
     server_name  localhost;

     location /demo/{
         proxy_pass  http://localhost:8080/demo/;
     }
 }