this is the configuration with which we are working, nginx v1.4.4, the error message is as follows "WebSocket is closed before the connection is established".

index.html

<script src="socket.io/socket.io.js"></script>

<script>

var websocket = io.connect("/");
$(document).on("ready", iniciar);
function iniciar(e)
{
   websocket.emit('my other event', { my: 'data' });
}
  
  
</script>

nginx.conf

# HTTPS server

upstream node {
    server 127.0.0.1:8080;
    keepalive 256; # not necessary
}


server {
    listen       443 ssl;
    server_name  misite.com www.misite.com;
    root /var/www/html/misite;

    access_log /var/log/nginx/misite.access.log;
    error_log /var/log/nginx/misite.error.log;
 
    ssl_certificate      /etc/nginx/ssl/misite.crt;
    ssl_certificate_key  /etc/nginx/ssl/misite.key;

    location / {
         rewrite ^/([\.a-zA-Z0-9_-]*)/?$ index.php?d1=$1 last;
         rewrite ^/([\.a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/?$ index.php?d1=$1&d2=$2 last;
         rewrite ^/([\.a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/?$ index.php?d1=$1&d2=$2&d3=$3 last;
         rewrite ^/([\.a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/([a-zA-Z0-9_-]*)/?$ index.php?d1=$1&d2=$2&d3=$3&d4=$4 last;
         rewrite_log on;

         index  index.html index.htm index.php;
    }

    location ~ \.php$ {       
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_index  index.php;
        fastcgi_param  SCRIPT_FILENAME  /var/www/html/misite/$fastcgi_script_name;
        include        fastcgi_params;
    }

    location /socket.io/  {

       # the following is required for WebSockets
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header X-NginX-Proxy true;

        # supposedly prevents 502 bad gateway error;
        # ultimately not necessary in my case
        proxy_buffers 8 32k;
        proxy_buffer_size 64k;
        #proxy_busy_buffers_size 10m;

        # the following is required
        proxy_pass  http://node;
        proxy_redirect off;

        # the following is required as well for WebSockets
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}