So - you know a bit of JS, and come from Europe/Asia/Africa / South America / Australia?
Be a champ and participate in little project of adding your national holidays to this repo:
Looking for Italian, French, UK, Ireland and various other Europe and other country coders willing to help out, in their native language.
Countries already taken / done:
Switzerland [maybe not your region]
India [maybe not your region]
United Kingdom [thanks]
You can contribute with 1 simple JS file that lists dates and holidays.
Look for completed files for reference.