PHP
Introduction
1. PHP is a powerful tool for making dynamic and interactive Web pages.
2. PHP is the widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
3. In our PHP tutorial you will learn about PHP, and how to execute scripts on your server.
4. PHP is a server-side scripting language.
What is PHP?
- PHP stands for PHP: Hypertext Preprocessor
- PHP is a server-side scripting language, like ASP
- PHP scripts are executed on the server
- PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
- PHP is an open source software
- PHP is free to download and use
What is a PHP File?
- PHP files can contain text, HTML tags and scripts
- PHP files are returned to the browser as plain HTML
- PHP files have a file extension of ".php", ".php3", or ".phtml"
What is MySQL?
- MySQL is a database server
- MySQL is ideal for both small and large applications
- MySQL supports standard SQL
- MySQL compiles on a number of platforms
- MySQL is free to download and use
PHP + MySQL
- PHP combined with MySQL are cross-platform (you can develop in Windows and serve on a Unix platform)
Why PHP?
- PHP runs on different platforms (Windows, Linux, Unix, etc.)
- PHP is compatible with almost all servers used today (Apache, IIS, etc.)
- PHP is FREE to download from the official PHP resource: www.php.net
- PHP is easy to learn and runs efficiently on the server side
Where to Start?
To get access to a web server with PHP support, you can:- Install Apache (or IIS) on your own server, install PHP, and MySQL
- Or find a web hosting plan with PHP and MySQL support
PHP Syntax
PHP code is executed on the server, and the plain HTML result is sent to the browser.
Basic PHP Syntax
A PHP scripting block always starts with <?php and ends with ?>. A PHP scripting block can be placed anywhere in the document.On servers with shorthand support enabled you can start a scripting block with <? and end with ?>.
For maximum compatibility, we recommend that you use the standard form (<?php) rather than the shorthand form.
<?php ?> |
Below, we have an example of a simple PHP script which sends the text "Hello World" to the browser:
<html> <body> <?php echo "Hello World"; ?> </body> </html> |
There are two basic statements to output text with PHP: echo and print. In the example above we have used the echo statement to output the text "Hello World".
Note: The file must have the .php extension. If the file has a .html extension, the PHP code will not be executed.
Comments in PHP
In PHP, we use // to make a single-line comment or /* and */ to make a large comment block. <html> <body> <?php //This is a comment /* This is a comment block */ ?> </body> </html> |
PHP Variables
Variables are used for storing values, such as numbers, strings or function results, so that they can be used many times in a script.
Variables in PHP
Variables are used for storing a values, like text strings, numbers or arrays.When a variable is set it can be used over and over again in your script
All variables in PHP start with a $ sign symbol.
The correct way of setting a variable in PHP:
$var_name = value; |
Let's try creating a variable with a string, and a variable with a number:
<?php $txt = "Hello World!"; $number = 16; ?> |
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