server side independant application

found a lot of close answers but nothing corresponding exactly to what i'm working for, so here goes.

i have a web application (html/css front end, js ajax calls to php scripts on server) which i guess i can officially call a client server web application and which is working fine.

what i would like to do is create a secondary application that runs on the server but does not need to be triggered by a call from the server or the client. for example, imagine this application continually calculates the time in different timezones, and for the sake of example each calculation takes 2 minutes: - what i see everywhere is a call from the client ( a button with Paris timezone) which sends an ajax call to the php calculator which launches and 2min later sends the reponse - what i want is for the server application to be continuously calculating it alone by itself so when i make a call to it i take the most recent calculation instead of waiting 2mins for a new one to be made

i hope this is clear, can someone tell me if this is feasible via php ?

thanks