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PHP Tutorial

PHP Introduction

PHP 5 Installation

PHP 5 Syntax

PHP 5 Variables

PHP 5 echo and print Statements

PHP 5 Data Types

PHP 5 String Functions

PHP 5 Constants

PHP Arithmetic Operators

PHP 5 if...else...elseif Statements

PHP 5 switch Statement

PHP 5 while Loops

PHP 5 for Loops

PHP 5 Functions

PHP 5 Arrays

PHP 5 Sorting Arrays

PHP 5 Superglobals

PHP Forms

PHP 5 Form Handling

PHP 5 Form Validation

PHP 5 Forms - Required Fields

PHP 5 Forms E-mail /URL

PHP Form Complete

PHP Advanced

PHP 5 Multidimensional Arrays

PHP 5 Date and Time

PHP Include Files

PHP File Handling

PHP File Open/Read

PHP File Create/Write

PHP File Upload

PHP Cookies

PHP Sessions

PHP E-mail

PHP Secure E-mails

PHP Error Handling

PHP Exception Handling

PHP Filter

PHP Database

PHP MySQL Introduction

PHP MySQL Connect

PHP Create DB/Tables

PHP MySQL Insert Into

PHP MySQL Select


PHP Order By

PHP Update

PHP Delete



PHP 5 Syntax

he PHP script is executed on the server, and the plain HTML result is sent back to the browser.

Basic PHP Syntax

A PHP script can be placed anywhere in the document.

A PHP script starts with <?php and ends with ?>:

// PHP code goes here

The default file extension for PHP files is ".php".

A PHP file normally contains HTML tags, and some PHP scripting code.

Below, we have an example of a simple PHP file, with a PHP script that uses a built-in PHP function "echo" to output the text "Hello World!" on a web page:


<!DOCTYPE html>

<h1>My first PHP page</h1>

echo "Hello World!";


ote: PHP statements are terminated by semicolon (;). The closing tag of a block of PHP code also automatically implies a semicolon (so you do not have to have a semicolon terminating the last line of a PHP block).

Comments in PHP

A comment in PHP code is a line that is not read/executed as part of the program. Its only purpose is to be read by someone who is editing the code!

Comments are useful for:

  • To let others understand what you are doing - Comments let other programmers understand what you were doing in each step (if you work in a group)
  • To remind yourself what you did - Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code

PHP supports three ways of commenting:


<!DOCTYPE html>

// This is a single line comment

# This is also a single line comment

This is a multiple lines comment block
that spans over more than
one line


PHP Case Sensitivity

In PHP, all user-defined functions, classes, and keywords (e.g. if, else, while, echo, etc.) are NOT case-sensitive.

In the example below, all three echo statements below are legal (and equal):


<!DOCTYPE html>

ECHO "Hello World!<br>";
echo "Hello World!<br>";
EcHo "Hello World!<br>";


However; in PHP, all variables are case-sensitive.

In the example below, only the first statement will display the value of the $color variable (this is because $color, $COLOR, and $coLOR are treated as three different variables):


<!DOCTYPE html>

echo "My car is " . $color . "<br>";
echo "My house is " . $COLOR . "<br>";
echo "My boat is " . $coLOR . "<br>";