PHP 101 (Part 1) - Secret Agent Man - Bond...James Bond (
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Once
you've configured your Web server to parse PHP pages, it's time to test it and
see if everything's working as advertised. The simplest way to do this is to pop
open your favourite text editor and create a file containing these lines of
code:
<?php
phpinfo();
?>
Save the file with the extension .php - for example,
"test.php"
Now, start up your Web browser and point it to the file you
just saved - for example, http://localhost/test.php - and you'll see a page
filled with what at first glance appears to be gibberish, but on closer
inspection will reveal itself to be a list of internal PHP variables. The values
of most of these variables can be modified by altering the "php.ini" file that
ships with every distribution of PHP. For beginners, the default values are more
than sufficient to work with.
There's one essential concept that you need
to get your mind around before we proceed further. Unlike CGI scripts, which
require you to write code to output HTML, PHP lets you create embed PHP code in
regular HTML pages, and execute the embedded PHP code when the page is
requested.
These embedded PHP commands are enclosed within special start
and end tags - here's what they look like:
<?php
... PHP code ...
?>
or the shorter version
<?
... PHP code ...
?>
Here's a simple example which demonstrates how PHP and HTML
can be combined:
<html>
<head>
<title>Bonding With PHP</title>
</head>
<body>
So who do you think you are, anyhow?
<br>
<?php
// this is all PHP code
echo "<b>The name's Bond...James Bond!</b>";
?>
</body>
</html>
And if you browse to this page through your browser and take
a look at the HTML source, this is what you'll see:
<html>
<head>
<title>Bonding With PHP</title>
</head>
<body>
So who do you think you are, anyhow?
<br>
<b>The name's Bond...James Bond!</b>
</body>
</html>
Every PHP statement ends in a semi-colon - this convention is
identical to that used in Perl, and omitting the semi-colon is one of the most
common mistakes newbies make. It's also possible to add comments to your PHP
code, as we've done in the example above. PHP supports both single-line and
multi-line comment blocks - take a look:
<?php
// this is a single-line comment
/* and this is a
multi-line
comment */
?>
