Page Title

learn basic PHP

PHP INTRODUCTION

what you should already know

HTML
CSS
JAVA SCRIPT

what is PHP?

PHP is an acronym for "PHP: Hypertext Preprocessor"
PHP is a widely-used, open source scripting language
PHP scripts are executed on the server
PHP is free to download and use
PHP is an amazing and popular language!
It is powerful enough to be at the core of the biggest blogging system on the web (WordPress)!
It is deep enough to run the largest social network (Facebook)!
It is also easy enough to be a beginner's first server side language!

What is a PHP File?

PHP files can contain text, HTML, CSS, JavaScript, and PHP code
PHP code are executed on the server, and the result is returned to the browser as plain HTML
PHP files have extension ".php"

What Can PHP Do?

PHP can generate dynamic page content
PHP can create, open, read, write, delete, and close files on the server
PHP can collect form data
PHP can send and receive cookies
PHP can add, delete, modify data in your database
PHP can be used to control user-access
PHP can encrypt data

note:With PHP you are not limited to output HTML. You can output images, PDF files, and even Flash movies. You can also output any text, such as XHTML and XML.

Why PHP?

PHP runs on various platforms (Windows, Linux, Unix, Mac OS X, etc.)
PHP is compatible with almost all servers used today (Apache, IIS, etc.)
PHP supports a wide range of databases
PHP is free. Download it from the official PHP resource: www.php.net
PHP is easy to learn and runs efficiently on the server side

PHP INSTALL

What do i need?

to start using PHP you can

Find a web host with PHP and MySQL support
Install a web server on your own PC, and then install PHP and MySQL

Use a Web Host With PHP Support?

If your server has activated support for PHP you do not need to do anything. Just create some .php files, place them in your web directory, and the server will automatically parse them for you. You do not need to compile anything or install any extra tools. Because PHP is free, most web hosts offer PHP support.

Set Up PHP on Your Own PC

However, if your server does not support PHP, you must:

install a web server
install PHP
install a database, such as MySQL

The official PHP website (PHP.net) has installation instructions for PHP: click here

PHP SYNTAX

Basic PHP Syntax

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


 <?php
// 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:

example


<!DOCTYPE html>
<html>
<body>

<?php

echo "hello world";
?>

</body>
</html>

run example

note:PHP statements end with a semicolon (;).

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 looking at the code. Comments can be used to:

Let others understand what you are doing
Remind yourself of 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 several ways of commenting:

example


 <!DOCTYPE html>
<html>
<body>

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

# This is also a single-line comment

/*
This is a multiple-lines comment block
that spans over multiple
lines
*/

// You can also use comments to leave out parts of a code line
$x = 5 /* + 15 */ + 5;
echo $x;
?>

</body>
</html>

run example

PHP case sensitivity

In PHP, NO keywords (e.g. if, else, while, echo, etc.), classes, functions, and user-defined functions are case-sensitive. In the example below, all three echo statements below are legal (and equal):

example


<!DOCTYPE html>
<html>
<body>

<?php
echo "hello world<br>";
ECHO "hello world<br>";
EcHo "hello world<br>";
?>

</body>
</html>

run example

However; all variable names 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):

example


<!DOCTYPE html>
<html>
<body>

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

</body>
</html>

run example

PHP variables

creating PHP varibles

varibles are containers for storing information

In PHP, a variable starts with the $ sign, followed by the name of the variable:

example


<!DOCTYPE html>
<html>
<body>

<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;

?>

</body>
</html>

run example

After the execution of the statements above, the variable $txt will hold the value Hello world!, the variable $x will hold the value 5, and the variable $y will hold the value 10.5.

note:When you assign a text value to a variable, put quotes around the value.
note:Unlike other programming languages, PHP has no command for declaring a variable. It is created the moment you first assign a value to it.

PHP variables

A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). Rules for PHP variables:

A variable starts with the $ sign, followed by the name of the variable
A variable name must start with a letter or the underscore character
A variable name cannot start with a number
A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
Variable names are case-sensitive ($age and $AGE are two different variables)

Remember that PHP variable names are case-sensitive!

output variables

The PHP echo statement is often used to output data to the screen.
The following example will show how to output text and a variable:

example


<!DOCTYPE html>
<html>
<body>

<?php
$txt = "W3Schools.com";
echo "I love $txt!";
?>

</body>
</html>

run example

learn basic php