Understanding PHP Syntax and Tags

Tutorial 2 of 5

Introduction

Tutorial Goal

The goal of this tutorial is to provide a comprehensive understanding of PHP syntax and tags. We will discuss the standard rules for writing PHP scripts and how to embed PHP in an HTML document.

What You'll Learn

By the end of this tutorial, you will be able to:

Understand and write PHP syntax
Use different types of PHP tags
Embed PHP codes within HTML

Prerequisites

Basic knowledge of HTML is required. Familiarity with programming concepts would be beneficial but not necessary.

Step-by-Step Guide

PHP Syntax

A PHP script can be placed anywhere in the document and starts with <?php and ends with ?>.

<?php
// PHP code goes here
?>

PHP Case Sensitivity

In PHP, all keywords, classes, functions, and user-defined functions are NOT case-sensitive.

<?php
echo "Hello, world!";
ECHO "Hello, world!";
EcHo "Hello, world!";
?>

All three echo statements above are legal and will print "Hello, world!".

PHP Comments

Comments in PHP are similar to other programming languages. Comments can be single-line (// or #) or multi-line (/.../).

<?php
// This is a single-line comment

# This is also a single-line comment

/* 
This is a 
multi-line 
comment
*/
?>

PHP Tags

PHP tags are the markers that tell where the PHP code begins and ends. There are four different pairs of opening and closing tags which can be used in PHP.

<?php //...?>   Standard PHP tags.
<? //...?>       Short open tags (only available if enabled in php.ini file).
<script language="php"> //... </script>   Script tags.
<% //... %>     ASP-style tags (only available if enabled in php.ini file).

It's recommended to use standard PHP tags as they always work regardless of the configuration settings.

Code Examples

Basic PHP Syntax

<?php
echo "Hello, World!";
?>

In this code, <?php is the opening tag for PHP code and ?> is the closing tag. echo is a language construct that outputs one or more strings. The string "Hello, World!" is printed when this script is run.

Embedding PHP in HTML

<!DOCTYPE html>
<html>
<body>
<h1>Welcome to My Homepage</h1>
<?php
echo "Hello, World!";
?>
</body>
</html>

In this example, PHP code is embedded within an HTML document. When the script is run, it will display a webpage with the heading "Welcome to my Homepage" and the text "Hello, World!".

Summary

In this tutorial, we've learned about PHP syntax and tags. We've seen how to write PHP scripts and embed them in HTML. We've also discussed the case sensitivity in PHP and how to write comments in PHP.

Practice Exercises

Write a PHP script that outputs "Hello, PHP!".
Write a PHP script embedded in an HTML document that outputs "PHP is fun!" in an h2 tag.
Modify the script in exercise 2 to add a comment that describes what the script does.

Additional Resources

PHP Official Documentation (https://www.php.net/manual/en/)
PHP: The Right Way (https://phptherightway.com/)
W3Schools PHP Tutorial (https://www.w3schools.com/php/)

Remember, practice is key in mastering any programming language. Happy coding!