What is PHP? <?php … ?>
PHP (Hypertext Preprocessor) is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. PHP is a scripting language designed to fill the gap between SSI (Server Side Includes) and Perl, intended largely for the web environment. PHP has gained quite a following in recent times, and it is one of the forerunners in the Open Source software movement. Its popularity derives from its C-like syntax, and its simplicity. PHP is currently divided into two major versions: PHP 4 and PHP 5, although PHP 4 is deprecated and is no longer developed or supplied with critical bug fixes. PHP 6 is currently under development.
PHP started out as a small open source project that evolved as more and more people found out how useful it was. Rasmus Lerdorf unleashed the first version of PHP way back in 1994.
- PHP is a server side scripting language that is embedded in HTML. It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites.
- It is integrated with a number of popular databases, including MySQL, PostgreSQL, Oracle, Sybase, Informix, and Microsoft SQL Server.
- PHP is pleasingly zippy in its execution, especially when compiled as an Apache module on the Unix side. The MySQL server, once started, executes even very complex queries with huge result sets in record-setting time.
- PHP supports a large number of major protocols such as POP3, IMAP, and LDAP.
Common uses of PHP:
- Access control on websites / web applications using php. you can restrict users to access some pages of your website.
- PHP performs system functions, i.e. from files on a system it can create, open, read, write, and close them.
- PHP can handle forms, i.e. gather data from files, save data to a file, through email you can send data, return data to the user.
- You add, delete, modify elements within your database through PHP.
- Access cookies variables and set cookies.
- It can encrypt data.
“Hello Web World” Script in PHP:
To get a taste of PHP, first start with simple PHP scripts. Since “Hello, Web World!” is an essential example, first we will create a friendly little “Hello, World!” script.
As mentioned earlier, PHP is embedded in HTML. That means that in amongst your normal HTML (or XHTML if you’re cutting-edge) you’ll have PHP statements like this:
<html> <head> <title>Hello Web World</title> <body> <?php echo "Hello, Web World!";?> </body> </html>
It will produce following result:
Hello, Web World!
If you examine the HTML output of the above example, you’ll notice that the PHP code is not present in the file sent from the server to your Web browser. All of the PHP present in the Web page is processed and stripped from the page; the only thing returned to the client from the Web server is pure HTML output.
All PHP code must be included inside one of the three special markup tags ate are recognised by the PHP Parser.
<?php PHP code goes here ?> <? PHP code goes here ?> <script language="php"> PHP code goes here </script>
Most common tag is the <?php…?> and we will also use same tag in our tutorial.
From the next chapter we will start with PHP Environment Setup on your machine and then we will dig out almost all concepts related to PHP to make you comfortable with the PHP language.
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PHP uh.. never heard of it ? what is php?
php a hypertext preprocessor?
A powerful server-side-scripting language, PHP.