there actually is already a script for that, called Wanikani Improve, but you can’t really find it anymore and it hasn’t been maintained for 2 years or so, so it doesn’t work without some tweaking. I still have it from back then.
I don’t want to suggest to drop yours, because having a script for this that is still being maintained is definitely useful. You might want to consider to copy a feature from WaniKani Improve though:
It has a button to show you the definition from the last item and what your answer was. It also shows by color coding of the button if there were other possible answers around, or if your answer wasn’t spot on and the typo correcter jumped in (mostly these are the cases where you use the button, to check if it really was a typo or if your answer was wrong).