Welcome to part 3 of my 10 part series on PHP. In the first two parts I introduced you to the language and to what software you needed to run it.
In this episode we will look at some simple PHP syntax, and we'll write a couple of small scripts to get our feet wet, and get a feel for the language.
What does a PHP script look like?
PHP traditionally is embedded into HTML code within a web page, as this was its initial intent. However it's becoming increasingly more popular for web application authors to write and generate the HTML using PHP from a page that is made entirely of PHP code.
The following two examples of the world renowned hello world program should help to show the difference:
Embedding in HTML
<html>
  <head>
    <title><?php print "My First Script"; ?></title>
  </head>
  <body>
    <?php
        
        print "<h1>Hello World</h1>";

      ?>
    </body>
  </html>
Full PHP

  <?php

    $content 
"<html>\n\t<head>\n\t\t<title>";
    
$content .= "My First Script";
    
$content .= "</title>\n\t</head>\n";
    
$content .= "\t<body>\n\t<h1>";
    
$content .= "Hello World";
    
$content .= "</h1>\n</body>\n</html>";

    print 
$content;

  
?>
Edited for correctness
When run using your web server set up, both scripts will produce the following:
  <html>
    <head>
      <title>My First Script</title>
    </head>
    <body>
      <h1>Hello World</h1>
    </body>
  </html>
My personal preference is embedding the PHP code within the HTML code, however there are plenty of alternative theories out there, and I would encourage you to explore and develop your own style of writing scripts.
As an example if you ever decide to work with the Typo3 framework (http://www.typo3.org/) then you'll be highly likely to use the Full PHP approach. For the remainder of this series we'll be using the embedded HTML approach.
The first script line by line
As you can see most PHP statements are included in special PHP tags which for the most part are no different to regular HTML tags.
Because of this, we can freely use them inter-changeably anywhere you would use any other HTML tags.
Looking at the title line in the first example above, you can see that we generate the title using PHP code and a static string. You could use a variable, but since we're not covering them until next time I'll skip over that for now.
So, what can I put in these PHP tags?
Well, anything that's valid PHP can go in there, print statements, function calls, variable assignments and so on, as an example using the print statement:

<?php

  phpinfo
();

?>
We are printing the output of the date function directly into a set of <H1> tags, which in this case is a string ready to be printed. Some functions however return different types such as arrays and resources, the good news is that in most cases PHP will try to format the output and display something useful.
For arrays however (We'll cover arrays in more detail in future article in the series) you'll likely want to use the print_r routine, for example:

<?php

  Print_r
($_POST);

?>
The small snippet above will display the contents of the POST array, something which can be very useful when testing forms of data. Simply create a PHP page with just the above in, and set it as the action in your HTML form tag, and hey- presto.
print_r will list the array items in sequence, and if wrapped up in <pre> tags will also lay the output out neatly line after line, as though it was being output to a terminal or command line.
One last useful tip that often aids in debugging is to output the phpinfo call, EG:

<?php

  phpinfo
();

?>
This provides a wealth of information about the environment PHP is running in, and can greatly help when first setting up your server, or when you need a quick reference of what extras you have installed.
For now we'll leave it there, but I would encourage you to read the online PHP Manual. Have a look at each of the function calls and see what they each return. Customize the script above to output different pieces of information.
Summary
In this episode we looked at our first script, and examined the ways in which it could be written, in the next episode we'll be looking at variables, the life blood of any program not least PHP, and remember don't be afraid to experiment, for the most part unless your playing carelessly with file functions, there's no damage you can do, one of the best places to learn is the PHP web site and the user code comments available.
Until next time.
Shawty
The ABC's of PHP Series
The ABC's of PHP
Introduction to PHP
What do I need to make it work?
Basic Script Building in PHP
How Variable Am I?
Strings & Text
Math & Number Handling in PHP
Introduction to Arrays and Hashes in PHP
Loops and Decisions in PHP
Advanced String Processing - How Regular Are Your Expressions