GET vs POST when requesting data on button click?

I'm using Laravel 5.3.

Essentially, when a user clicks a button on the screen, I need to get data from the database (using AJAX), and then display that data on the screen.

However, I'm not sure if I should be using a GET or POST request? I've only ever used GET requests for routing when the user wants to get to a specific page, like a GET request for /index or /profile.

Which should I use?

via Chebli Mohamed