That test on that site is broken due to their use of JavaScript and https. They should at the very least migrate to the http domain. Which is good actually because man in the middle attacks can occur when you do it improperly.
Man in the middle:
You <-> Net <-> Server
You <-> (Hacker) <-> Net <-> (Hacker) <-> Server
As is quite obvious, this is a basic way to phish / sniff the IP and all the other, more delicate data.