PHP & MySQL® Web Development All-in-One Desk Reference for Dummies®

2.5. Organizing Scripts

A script is a series of PHP statements, and each statement performs an action. PHP starts at the beginning of the script and executes each statement in turn. Some statements are complex statements that execute simple statements conditionally or repeatedly.

An application often consists of more than one PHP script. In general, one script performs one major task. For instance, an application might include a script to display a form and a script that stores the data in a database. However, this is a guideline, rather than a rule. Some scripts both display a form and process the form data.

Each script should be organized into sections for each specific task. Start each section with a comment describing what the section does. (We cover writing comments in Book II, Chapter 1.) Separate sections from each other with blank lines. For instance, a login script might have sections as follows:

#display the login form
  statements that display the login form

#check for valid user name and password
  statements that check for valid user name and password

#display first page of Web site or error message
  statements that display the site if user had valid login
  or error message if login invalid

The goal is to make the script as clear and understandable as possible. Scripts need to be maintained and updated over a period of time, often not by the person who created them. The more clear and understandable they are, the easier to maintain and update they are.

2.5.1. Separate ...