Limitations of PHP

The more I've learned about PHP, the more I realize how limited it is by itself. All PHP on a page runs before the page is even sent to a user's browser, which limits interactivity. Turns out another technology, AJAX, is needed to let to user communicate with the PHP and therefore interact. But then it turns out, AJAX isn't an individual thing, it's a collection itself.

However, javascript figures in prominently, which simplifies my life immensely. I took today off and relaxed, but tomorrow I shall return to the grind stone and see if I can come up with something more interesting than a page that tells you the date and time of log in.

EDIT: One thing that I've also realized is that there isn't much need to run PHP without reloading the page. The clock I wanted to write would be, but I can probably do that entire with jQuery.