failed to connect to Openfire by websocket

OF version:3.9.1, I can use pidgin to log on.

When using strophe.js, I tried BOSH first, but it fails, probably I didn't get apache settings right. Then I decide to try websockets, and this is my preferred option, however, I got the following error message:

WebSocket connection to 'ws://ikan.tk:7070/ws/server' failed: WebSocket is closed before the connection is established.

then the status is "connecting" always.

Questions:

1. what's the URL for websocket? using http-bind port (7070), or the client port (5222)? Any path (like /ws/server) to be followed ?

2. I'm using OF 3.9.1 on windows, no plugin installed. Does OF 3.9.1 support WS by default, or I have to install some plugin, or there's some configuration items I need to do?

Thanks in advance!