I just saw this.  You can't disable TLS, but I have a gist up on my github which demonstrates how to connect via TLS that I've tested with firefox and chrome:

https://gist.github.com/davecgh/8a16b1048fe0fb406d29

Make sure you modify the username and password near the top of the file in the javascript to the correct values or you'll get an undefined error since btcd will immediately disconnect you upon receiving invalid credentials.