The URL you gave uses an insecure server. Many features are unavailable on insecure servers, including IIRC device motion. (There have been security vulnerabilities reported where the device motion can be used to guess what the user is typing on an on-screen keyboard, so it is regarded as a security-sensitive feature.)
These days you should host everything on a secure server (HTTPS) from the start. You can't really get away with insecure servers any more.