I know that php is a server-side language. However I am confused on how to hook up a html button event to a page that uses php. I understand this will probably involve Javascript, some css and html and maybe Ajax. I've been looking at some examples but they don't explain the important pieces I am looking for. In summary I want to see the code for the click event and how php gets notified there was a click.
I apologize if this is a strange question. I'm used to old application programming and I'm trying to understand some of these newer practices.