I have been into web development with both client amd server side code, and have been using JavaScript Ajax
to receive and manipulate for data along with PHP scripts.
However, I noticed that websites like Google and Facebook use PHP forms instead of sending ajax requests
to PHP scripts.
What I wonder is that what is the advantage of direct PHP form submit over sending form data from a static HTML page to a PHP Script via JavaScript Ajax, especially from the UX and security point of view?