How I can create a ICS Timetable that always is new generated?

Question

The goal is to create a timetable for school that is possible to add in a outlook or google calendar. if the timetable is resheduled, the calendars should refresh with the new dates and times.should be possible like to subscribe the ics file.

I have created already a ics file that is generated, but if you add this "static" file no update is on the client site. you have to add the ics file again.
If you have some better idea for the program language than php and html, please publish too.

Thanks for help :)

Answer 1

some json pulling if available

Answer 2

thanks for the answer. good idea.. do you have some example or link? i haven't so much know-how in javascript and json.
are there requirements for the webserver?