The page has been updated, and the source code is here:
https://github.com/whatsapp/WhatsAPI/
Based off https://github.com/venomous0x/WhatsAPI
Have you played with the node.js clients?
Tried using this source. Can't seem to get the number and MAC combination right.
Using my own phone and account BTW.
What's ur device ? (Android or iOS ?)
edit
Worked for my android. Still not working for iOS.
First impression for most users would be that this is credential harvesting webpage with who knows what running behind it.