Chapter 24. Working with Cookies and Sessions

IN THIS CHAPTER Why do you need sessions? How PHP sessions are implemented Cookies and their use Sending HTTP headers with PHP

This chapter might as well have been called "Keeping Track," because its theme throughout is the problem of tracking interactions with users over longer periods of time than it takes to generate a single web page. We explain the extent of PHP support for extended user sessions and for setting and checking cookies, and then cover a couple of related techniques involving directly sending HTTP headers.