Why is console.log an empty function on some sites in Chrome?

Question

Go to Twitter\'s login page and type the following in the console:

window.addEventListener(\'keypress\', function(e){console.log(\'hello\')}, true)

Answer 1

This problem doesn't occur on Firefox.

I've checked on Chrome and apparently for some reason the Gmail and Twitter pages end up reassigning console.log to an empty function function () {}, so your handler gets called but it does nothing. If you try alert() instead of console.log, you'll see it working.

Interesting.