A few years ago, I wrote a series of posts discussing how to use Ajax in the WordPress Frontend. The purpose of the series is simple:
We’re going to give a very brief overview of what Ajax is, how it works, how to set it up on the front, and understanding the hooks that WordPress provides. We’ll also actually build a small project that puts the theory into practice. We’ll walk through the source code and we’ll also make sure it’s available on GitHub, as well.
Generally speaking, the series holds up well but, as with all software under constant development, techniques, APIs, and approaches change. Furthermore, as years pass and we continue to refine our skills, we get better at development and we get better at employing new APIs.