PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

Logging In and Out
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The four main sections of the script are as follows:
1. You do some processing that must take place before you send the page header to
the browser, such as starting the session, executing any preprocessing for the action
the user has selected, and deciding what the headers will look like.
2. You process and send the appropriate headers and menu bar for the action the user
has selected.
3. You choose which body of the script to execute, depending on the selected action.
The different actions trigger different function calls.
4. You send the page footers.
If you look briefly through the code for the script, you will see that these four sections
are marked with comments.
To understand this script fully, let’s walk through actually using the site action by action.
Logging In and Out
When a user loads the page index.php, he will see the output shown in Figure 29.2.
Figure 29.2
The login screen for Warm Mail asks for a username and password.