Introduction To PHP -1
Your PHP program is responsible for passing back a clean file suitable for display in a
web browser. At its very simplest, a PHP document will output only HTML. To prove
this, you can take any normal HTML document such as an index.html file and save it
as index.php, and it will display identically to the original.
To trigger the PHP commands, you need to learn a new tag. The first part is:
<?php
The first thing you may notice is that the tag has not been closed. This is because entire
sections of PHP can be placed inside this tag, and they finish only when the closing part
is encountered, which looks like this:
?>
A small PHP “Hello World” program might look like Example 3-1.
Example 3-1. Invoking PHP
<?php
echo "Hello world";
?>
The way you use this tag is quite flexible. Some programmers open the tag at the start
of a document and close it right at the end, outputting any HTML directly from PHP
commands.
Others, however, choose to insert only the smallest possible fragments of PHP within
these tags wherever dynamic scripting is required, leaving the rest of the document in
standard HTML.
The latter type of programmer generally argues that their style of coding results in faster
code, while the former says that the speed increase is so minimal that it doesn’t justify
the additional complexity of dropping in and out of PHP many times in a single
document.
As you learn more, you will surely discover your preferred style of PHP development,
but for the sake of making the examples in this book easier to follow, I have adopted the
approach of keeping the number of transfers between PHP and HTML to a minimum—
generally only once or twice in a document.
By the way, there is a slight variation to the PHP syntax. If you browse the Internet for
PHP examples, you may also encounter code where the opening and closing syntax
looks like this:
<?
echo "Hello world";
?>
web browser. At its very simplest, a PHP document will output only HTML. To prove
this, you can take any normal HTML document such as an index.html file and save it
as index.php, and it will display identically to the original.
To trigger the PHP commands, you need to learn a new tag. The first part is:
<?php
The first thing you may notice is that the tag has not been closed. This is because entire
sections of PHP can be placed inside this tag, and they finish only when the closing part
is encountered, which looks like this:
?>
A small PHP “Hello World” program might look like Example 3-1.
Example 3-1. Invoking PHP
<?php
echo "Hello world";
?>
The way you use this tag is quite flexible. Some programmers open the tag at the start
of a document and close it right at the end, outputting any HTML directly from PHP
commands.
Others, however, choose to insert only the smallest possible fragments of PHP within
these tags wherever dynamic scripting is required, leaving the rest of the document in
standard HTML.
The latter type of programmer generally argues that their style of coding results in faster
code, while the former says that the speed increase is so minimal that it doesn’t justify
the additional complexity of dropping in and out of PHP many times in a single
document.
As you learn more, you will surely discover your preferred style of PHP development,
but for the sake of making the examples in this book easier to follow, I have adopted the
approach of keeping the number of transfers between PHP and HTML to a minimum—
generally only once or twice in a document.
By the way, there is a slight variation to the PHP syntax. If you browse the Internet for
PHP examples, you may also encounter code where the opening and closing syntax
looks like this:
<?
echo "Hello world";
?>
