Here’s something that might be a worthwhile extension to FireFox.
If I am keying in some paper forms with numeric values (1 to 5) or yes/no (y/n or 0/1), rather than mousing around and clicking or tabbing and spacebar-pressing, wouldn’t it be useful to simply tab between answers and then hit the correct value on the keypad? So instead of tabbing across to 10 on a field with answers from 1 to 10, I could use type “1 0” on the keypad and tab to get to the next field.