How do I make my browser brute force an input field?

There's a website I frequent that gives codes such as GD??Q-TPY32-TPTT3-9CM9P-F2QMQ and hints that the ?? is a number and a letter. If you're the first to unlock the code you can redeem the modest prize.

So the obvious way to solve this problem is to brute-force the code. But obviously I don't want to sit in front of the computer for an hour to manually input all 10 * 26 combinations. Is there a way for me to tell my browser to input these codes (assume that each 开发者_运维问答5-character block is an individual text field). Or is there a special browser that enables some sort of macro-type feature? Thanks.

Firefox or Chrome + Greasemonkey extension

But you don't need a browser, you can use any language and an HTTP library.