Thanks! It turned out to be a bit trickier than I thought to allow changing the keyboard shortcuts at runtime, so I haven't implemented that yet. But in the meantime, you could probably use a workaround similar to this one:
You can use this handy tool to find the codes for different keys. The code for the x key would be 88
.
Within the event listener block, you should then be able to add something like this to submit a "reject" answer if the 3 key is pressed:
if (event.keyCode === 51) { // key code for "3"
window.prodigy.answer('reject')
}
(Just keep in mind that the number keys are also used in the choice interface to allow selecting the different options. So if you're using that interface, you might get a clash here.)