1, Nginx settings are as follows

-sharp websocket
upstream wss_svr {
    server 192.168.213.182:1234 weight=1;  
}
 
-sharp 443 sslwebsocketswss
server {
 
    listen 443;
    server_name www.a.com;
        
    ssl on;
 
    -sharp nginx.conf
    ssl_certificate dhxtest.crt;
    ssl_certificate_key dhxtest_nopass.key;
        
    ssl_session_timeout 5m;
    ssl_session_cache shared:SSL:10m;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2 SSLv2 SSLv3;
    ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
    ssl_prefer_server_ciphers on;
    ssl_verify_client off;
        
    location / {        
        proxy_redirect off;
        proxy_pass http://wss_svr;      -sharp 
        proxy_set_header Host $host;
        proxy_set_header X-Real_IP $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr:$remote_port;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;   -sharp 
        proxy_set_header Connection upgrade;
    }
        
}

2, the WebSocket connection is as follows

ws = new WebSocket("wss://www.a.com");
ws.onopen = function() {
    alert("");
    ws.send("tom");
    alert(":tom");
};
ws.onmessage = function(e) {
    alert(":" + e.data);
};

3. If you connect through a port, you can wss://www.a.com:1234