How to auto-update a single block in a PHP page?

Question

HTML

Hello!
Guys, an interesting question arose: how to automatically update a separate block on a page?
I know that you can update the entire page in this way after a given period of time (in this case, every 5 seconds): I need something similar, but not with the entire page, but, for example, with a separate . Does such a thing exist? and how can it be written?
<meta http-equiv="refresh" content="5">