PHP OVERVEIW

PHP Overview

• Before we start with php let’s over some general questions and concepts of php.
• First history of php.
• The first build of php was developed by Rasmus lerdorf in 1994 as a set of CGI binaries in the c programming language to replace a set of perl script that he uses to maintain his home page.
• The second version was a more formalized version that launched in 1995 this version was a more improved version of the first version and also combined with code the interpreter the data submitted by web forms that was the first public release of php. At beginning php is called “Personal Home Page Tools” stand as php Tools
• version three was released in 1998 with the version three php change a lot two more developers join in Andi Gutmans and Zeev Suraski they rewrote the major part of php in between 1997 and 1998 thay also rename it php:hypertext preprocessor.
• Version four was launch in 2000 and php change significantly again Andi Gutmans and Zeev Suraski form a new company  called zen and zen rewrote the core of php so code can easily work with other people's code they release it in may 2000 and core code is referred as zen engine 1.
• Php version 5 was launched in 2004 referred to as zen engine 2 with version 5 that provides better performance and improved object-oriented programming.

what is php?

• Php is a server side scripting language not a programming language so you ask what is the difference between the scripting language and programming language.as we go in depth with scripting language it becomes similar as programming language.but we can do the general comparison.
• A script run in response on an event script does not run on its own.it's only run when web page request script usually runs instruction in top to bottom manor.script have very little or no user interaction except the first inctaction.after following given instruction script close it self.
• A programming run even when it does not  respond to an event. It continues to run and wait for user interaction.programs usually have no start or end point because of complex instructions and have lots of user interaction.
• Php is a server side scripting language its totally opposite of client side scripting language. Client side scripting languages send the code to users browser and then run code on users system on the other hand server side scripting languages run the code on server then send the result to users browser. Since php runs on a web server. it generally can not run on its own.In order to run php code we need a running web server.php code does not compiled code is executed by a web server as it is written.php is designed to use with html(Hypertext markup language).it can be embedded with html or we can use it to generate html in the end php is going to return html to browser.php is going to be input and html is going to be the output.php files saved with “ .php ”extension it will tell the web server that file content php code and its need to be executed.html pages are static by it nature its show same content to every users.php let us create dynamic pages. Page context can change base on conditions it depend on user interaction or values in the database.php syntax is very similar to other c,java,perl etc language with few changes

why php.?

• Why we use php over other web technology first off all php is open source.since its open source is source code is available to everyone to read, user, study or modify.php is also cross platform its mean that you can run the script on any os(operating system).since php scripts run on server and result is sended to users browsers so it's doesn't matter which type of system user have.for example you can write php script in windows you can run same script without making any changes on any other os like mac or linux etc.php is also robust and scalable means it can handle large traffic and can be customized after deployment.php is fully object-oriented since version 5.
• Php is specifically designed for web development.php also has a large active developer community and also one of the best web development tools.