Connecting to HTML5 Websocket - html

Question

I'm a bit confused about HTML5 Websockets. I've looked at numerous tutorials out there and a lot of them have different variations of connecting using different ports. What do these ports mean?
Adobe for instance, uses this:
new WebSocket('ws://localhost:1740');
Then another tutorial has this where no ports are required:
new WebSocket("ws://www.websockets.org");
And finally a third tutorial has a port, but it's completely different:
new WebSocket("ws://localhost:8080/echo");
My question would be, why do these vary? How do I know which ports to connect to? Also, I've attempted to do my own connection:
var ws = new WebSocket("ws://test.ontarget-network.com/");
But I get the following error: Unexpected response code: 200
I've tested around and tried connecting to various other "ports" (not knowing what I'm doing obviously, typing in random numbers) and this error would disappear, however, my code
ws.onopen = function(){
alert("Connection Established");
};
would not execute.
I'm trying to fully understand HTML5's Websockets API so I can experiment and create more dynamic applications. Thanks for the help.

Answer 1

The server should have an endpoint that accepts WebSocket connections. So, if that endpoint is /echo you would want to connect to:
ws://localhost:8080/echo/websocket
You will get the Unexpected response code: 200 error if you exclude the /websocket suffix after the endpoint. I was having the same confusion and this link cleared things up a bit for me.

Answer 2

The following comes from the latest WebSocket draft:
By default the WebSocket protocol uses port 80 for regular WebSocket
connections and port 443 for WebSocket connections tunneled over TLS
[RFC2818].
Really though, you should be able to use any valid port not in use. As long as clients are trying to connect to the same port that the server-side script opens for the socket connection, you should be fine.
A quick note on ports:
Port 80 is the HTTP port.
Port 8080 is the alternate HTTP port.
Port 443 is the HTTPS (i.e., HTTP with TLS) port.
Port 1740 in the Adobe code seems like some random port not already in use by other services.
For a full list of preset ports, please see the following:
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
As for your "Unexpected response code: 200" error, I'm guessing that the WebSocket URL you're using on the client side is not pointing to a valid server-side script, but that's hard to comment on without more info.

Answer 3

I had the same issue, But to survive with
Unexpected response code: 200
You need to have either server-side script to handle the web socket, or you can use Node.js to build a you server script.
for the sake of education you can try to biuld your own websocket sever script.

Answer 4

Actually there is something else... You can not open a connection to every port since there is a list of blocked ports in every browser. I remember seeing the full list of ports in 'The tangled Web' from Michal Zalewski; however, I think a quick google will show this also.