Understanding the syntax of PHP is essential for anyone venturing into web development. This section provides an overview of the general PHP syntax and covers fundamental concepts.

Escaping to PHP

PHP code within a webpage can be identified by the following methods:

Canonical PHP Tags

These tags provide a clear and recommended way to embed PHP code in your files.

<?php
   // PHP code goes here
?>

Short-open Tags

Short-open tags offer a concise alternative but may require specific configurations. Ensure to enable them in your php.ini file if you choose this style.

<?
   // PHP code goes here
?>

ASP-like Tags

To use ASP-like tags, configure the php.ini file:

<%
   // PHP code goes here
%>

Configuring php.ini allows you to use ASP-like tags. However, note that this style is less common in modern PHP development.

HTML Script Tags

You can embed PHP within HTML script tags by specifying the language attribute.

<script language="PHP">
   // PHP code goes here
</script>

Commenting in PHP

PHP supports various methods for commenting code:

Single-line Comments with #

# This is a single-line comment

Single-line Comments with //

Single-line comments begin with either ‘#’ or ‘//’.

// This is also a single-line comment

Multi-line Comments with /* ... */

Multi-line comments use the /* ... */ syntax and are useful for longer explanations.

/*
   This is a multi-line comment
   spanning multiple lines
*/

Outputting Text in PHP

Let’s explore a simple “Hello World” example to understand different ways of outputting text in PHP

<?php
   print "Hello World";  // Using print
   echo "Hello World";   // Using echo
   printf("Hello World"); // Using printf
?>

Why three different ways to output?

• print returns a value, always 1.
• echo can take a comma-delimited list of arguments to output.
• printf is a direct analog of C’s printf().