You're being a bit disingenuous by not mentioning the inbuilt protections that the HTML5 Fullscreen API offers.

"Also, any alphanumeric keyboard input while in full-screen mode causes a warning message to appear; this is done to help guard against phishing attacks. The following keys are the only ones that don't cause this warning message to appear (...)"

(https://developer.mozilla.org/en-US/docs/DOM/Using_full-scre...)

The article and demo are nice though. Good work.