Similar kanji userscript?

Does anyone know if there is a userscript that would pull up similar kanji when you make a mistake. I find as I get further into the higher levels I keep getting kanji that are only off by one stroke mixed up, but because I can’t compare them immediately I end up confused the next time around as well. If there isn’t a userscript, does anyone know if there are any websites that make finding that information easier?

Don’t know about userscript, but kanjidamage shows lookalikes for kanji with some hints on how to differentiate them,
for example