如果div为空，如何修复onclick不会触发？

I am working on a backend site for members and volunteers of my scoutgroup. I have a calendar page which is just a nice table build from the database for every row the division has (there a 2 divisions). Only Fridays, Saturdays and Sundays are added. I do it this way because we are used to a google sheet.I am working on a backend site for members and