I just tested this under OSX and had no problem, so this is probably Windows-only.
"Today I installed Debian google-chrome-unstable and it also exhibits this issue."
One commenter (http://code.google.com/p/chromium/issues/detail?id=128339#c3) also claimed to have the issue on OS X specifically.
var sock = new window.WebSocket('wss://localhost:3000/echo');
>undefined
sock.send('hello');
>false