I want to create a calendar system, it is something like Google calendar allow users to post data but I have no idea I have to use a client or server side base on the calendar.
Any suggestion or tutorial about this?
I would suggest that you approach the question from the fact that you have to store, and visualize the data your users produce. To show the calendar, you will most likely need front end (client side) programming. To fetch and store the data, you will need a server side application. The upside is that if you get the server-side right, you can freely experiment with the client-side.