老师我这个详情页根据课程写完后还是这样的，即使看完整个课程，最后把教程代码拷贝到项目里也还是有这样的错误，已经在后端做了跨域。要怎么解决呢。在线等，急！
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老师可能因为我的是Ubuntu系统，和您的不太一样。这个是nginx.conf。

user root;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;


        server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
		# gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}


#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#}

然后我单独配置的是在和nginx.conf同级的目录下，sites-enable里。
如下

server {
        listen 81;
        listen [::]:81;

        root /var/www/ebook;
        #index index.html index.htm index.nginx-debian.html;
        autoindex on;
        server_name ebook www.ebook;

        location / {
                #try_files $uri $uri/ =404;
                add_header Access-Control-Allow-Origin *;
                add_header Cache-Control "no-cache, must-revalidate";
        }
}

现在这个情况是可以从详情页跳转到电子书阅读界面，但是进入阅读界面后封面那一页是空白只有主题颜色，但可以阅读和翻页。然后只这个详情页报出上述图片的错误。