Uh folks, key loggers (keystroke loggers) generally fall into the realm of spyware, so let's not get discussing them here. I will change the subject line.
What the OP apparently wants is to change their keyboard mapping so they can use Dvorak layout rather than the default QWERTY. Either the browser or the base operating system should provide keyboard maps for Dvorak input. I would be surprised if it's not possible in any given operating system. Besides Dvorak, there should be maps available for various European keyboards (e.g., AZERTY) and non-Latin keyboards and input methods (Cyrillic, Hebrew, Chinese, etc.).
If you're looking for how to write a keyboard map yourself, I can't help you with that, although there might be information floating around on the Web.