Specifications

way they did, when it was last modified, and so on. You will generally find comments in all

but the simplest PHP scripts.

The PHP interpreter will ignore any text in a comment. Essentially the PHP parser skips over

the comments that are equivalent to whitespace.

PHP supports C, C++, and shell script style comments.

This is a C-style, multiline comment that might appear at the start of our PHP script:

/* Author: Bob Smith

Last modified: April 10

This script processes the customer orders.

Multiline comments should begin with a /* and end with */. As in C, multiline comments can-

not be nested.

You can also use single line comments, either in the C++ style:

echo “<p>Order processed.”; // Start printing order

or in the shell script style:

echo “<p>Order processed.”; # Start printing order

With both of these styles, everything after the comment symbol (# or //) is a comment until

we reach the end of the line or the ending PHP tag, whichever comes first.

Adding Dynamic Content

So far, we haven’t used PHP to do anything we couldn’t have done with plain HTML.

The main reason for using a server-side scripting language is to be able to provide dynamic

content to a site’s users. This is an important application because content that changes accord-

ing to a user’s needs or over time will keep visitors coming back to a site. PHP allows us to do

this easily.

Let’s start with a simple example. Replace the PHP in processorder.php with the following

code:

echo “<p>Order processed at “;

echo date(“H:i, jS F”);

echo “<br>”;

In this code, we are using PHP’s built-in date() function to tell the customer the date and time

when his order was processed. This will be different each time the script is run. The output of

running the script on one occasion is shown in Figure 1.3.

PHP Crash Course

HAPTER 1

PHP CRASH

COURSE

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