There’s a number of ways, one common method is the button click event triggers a javascript or jquery function. This begins an AJAX or similar transaction where the function requests data from your server. If the data is successfully received, it is placed into a DOM container using the innerHTML method or equivalent.
The only thing the codex is really useful for is how to enqueue javascript and a brief AJAX ovewrview. Turn to the web in general for AJAX techniques, it is not specific to WordPress.
Thread Starter
j w
(@justinmwoodum)
Thanks for the great answer, bcworkz!