So I'm new to the programming side of webpages, but I'm trying to learn. I am in the process of making a single page website for a local radio group of roughly 20-30 members which may increase over time. They want to be able to show when they are online. The idea I had was basically to put a login field near the top of the website where they would input a "call name" and their real name, so 2 different fields. After clicking the submit button I want to populate a list\table(doesn't really matter which) to show that they are "online", and once the session has ended(closed the webpage) have it remove them from the list.
There doesn't need to be any security, no cached information, no cookies, and as simple as possible. How might I go about doing this? Any help is appreciated.