I need a php code that will return me some custom html which is different for every user on the WordPress site. For simplicity let’s say that I want to return the current time like so:

echo time();
exit()

The issue here (and the reason why I used exit()) is that this code runs in functions.php file of the website’s theme. I can’t move this to another file and I need the execution to stop. I believe that WordPress or something other on the website uses caching and the result of this is that the output of the code above is always the same. If I just do echo and let the page load naturally (which I don’t want), however, it works fine.

Is there any way to end execution without it being cached?