I am writing a PHP backend, JS/Jquery front end application that will allow users to "communicate" in near real time. That is the hope at least, my question is what is my best course of action? Am I best to use WebSockets to send data between the server and client or would use AJAX and some sort of timer (x amount of seconds) be better. My worry with the AJAX way is that it may be taxing on the server to have 10+ clients all asking for data every 15-30 seconds. I need it to be near real-time and so 5 minutes is not really realistic.
An example of what I am trying to do would be if I had 5 users all on a page and user 1 updates their status, I would want users 2,3,4, and 5 to see the update as fast as possible without having to refresh.
I am mixed on what I think is best and I don't want to start doing it one way and find out it is insecure or terrible after getting halfway done. What is my best route with an application like this?