PHP Introduction: What is PHP ?
"PHP: Hypertext Preprocessor"
PHP is a server side scripting language, widely used in internet programming.
We can develop pages with dynamic content by using PHP. By using PHP we can
interact with database servers and manage the page content accordingly.
Some important points about PHP
- PHP runs at Web server side.
- Your web browser at client end can’t execute PHP code.
- PHP script handles database and manages records at server end.
What we can do by using Php?
- Create member signup , login pages and store the details as records in a database.
- Create shopping cart for an e-commerce site
- Manage content of a website.
- Create a discussion forum.
- Create dynamic graphs and images, draw charts.
Download PHP Here
- It is free and open source
- PHP can run in many platforms like Linux , Windows , Max , Unix etc
- Works well with all Web server like Apache, IIS etc
- It can connect to may databases ( MSSL, Oracle, MySQL etc )
Let us take one simple example.
Simple codes of Beginners
You can read more on Installation of PHP here
PHP support and system
|php_info()||List of settings and configuration about PHP support|
|php_uname()||About server , OS , Host name, Machine type, version name|
|php_ini()||Server configuration file edit and update|
|ini_get()||Reading about the PHP settings of php.ini file settings|
|ini_set()||Changing ( some of the ) PHP settings at page level|
|php_ini_loaded_file()||Path of loaded php.ini file|
|PHP_VERSION()||What is the version of PHP the system is using|
When ever request comes for a static html or
htm page the web server returns the page to the client. Here script
processing or execution is not done. Such pages don't have dynamic
capability and content is fixed. In Windows server the web server is IIS and for Linux systems Apache web servers are generally used. However PHP and Apache runs well in Windows platform also. This site is supporting PHP on a Linux platform. In the same way the server can run other scripts like ASP, Perl etc. PHP can be downloaded from www.php.net
|Guide ||PHP beginners guide|
|echo()||Printing output using PHP|
|sleep()||Adding delay to script execution|
|Comments||Adding text to part of php code for better understanding and maintenance|
|Numbers||Printing numbers to screen using loop|
|Errors||Handling PHP errors during code execution|
Incase of PHP pages the server does not return
the page directly to the client. The web server runs the PHP engine and
the output of the executed script is posted back to the client
machine. Depending on the various input conditions the page content
can be changed. PHP can easily connect to MySQL database and this combination is very popular in the internet
The file extensions for PHP pages.
Web sites are organized at the server like we organize files and folders. So when we open a website one of the default file opens as home page of the site. Read here on how to fix the default page of a website . Usually files with php or php3 ( in old version of PHP ) extensions are files which contain PHP code. Same way we can say the files with .asp are the active server page files contains asp code. But this is not always true. At the server settings we can change the settings and tell the web server which type of files to execute through which engine or scripting language. A file with .htm extension can pass through php engine to execute php codes present inside. Read how IIS is set to pass different extensions through different engines.
However after executing different types engines the final script is posted to user browser which does not contain any PHP, ASP or any other types of scripting language and it only contains HTML and other client side scripts.
Answer these questions..
- By using PHP can we manage the layout of a web page ?
- Without installing PHP at the server can we execute a php file with php code inside ?
- Does the file extension matter ( by default without changing the settings ) at server end for executing scripts.
- Can I develop a member login script by using HTML
How to write our first PHP Script