Php web scripting language

What is PHP? Write your first PHP Program

PHP is a server side scripting language. that is used to develop Static websites or Dynamic websites or Web applications. PHP stands for Hypertext Pre-processor, that earlier stood for Personal Home Pages.

PHP scripts can only be interpreted on a server that has PHP installed.

The client computers accessing the PHP scripts require a web browser only.

A PHP file contains PHP tags and ends with the extension “.php”.

In this tutorial, you will learn-

What is a Scripting Language?

A script is a set of programming instructions that is interpreted at runtime.

A scripting language is a language that interprets scripts at runtime. Scripts are usually embedded into other software environments.

The purpose of the scripts is usually to enhance the performance or perform routine tasks for an application.

Server side scripts are interpreted on the server while client side scripts are interpreted by the client application.

PHP is a server side script that is interpreted on the server while JavaScript is an example of a client side script that is interpreted by the client browser. Both PHP and JavaScript can be embedded into HTML pages.

Programming Language Vs Scripting Language

Programming language	Scripting language
Has all the features needed to develop complete applications.	Mostly used for routine tasks
The code has to be compiled before it can be executed	The code is usually executed without compiling
Does not need to be embedded into other languages	Is usually embedded into other software environments.

What does PHP stand for?

PHP means – Personal Home Page, but it now stands for the recursive backronym PHP: Hypertext Preprocessor.

PHP code may be embedded into HTML code, or it can be used in combination with various web template systems, web content management system and web frameworks.

PHP Syntax

A PHP file can also contain tags such as HTML and client side scripts such as JavaScript.

• HTMLis an added advantage when learning PHP Language. You can even learn PHP without knowing HTML but it’s recommended you at least know the basics of HTML.
• Database management systems DBMS for database powered applications.
• For more advanced topics such as interactive applications and web services, you will need JavaScript and XML.

The flowchart diagram shown below illustrates the basic architecture of a PHP web application and how the server handles the requests.

Why use PHP?

You have obviously heard of a number of programming languages out there; you may be wondering why we would want to use PHP as our poison for the web programming. Below are some of the compelling reasons.

• PHP is open source and free.
• Short learning curve compared to other languages such as JSP, ASP etc.
• Large community document
• Most web hosting servers support PHP by default unlike other languages such as ASP that need IIS. This makes PHP a cost effective choice.
• PHP is regular updated to keep abreast with the latest technology trends.
• Other benefit that you get with PHP is that it’s a server side scripting language; this means you only need to install it on the server and client computers requesting for resources from the server do not need to have PHP installed; only a web browser would be enough.
• PHP has in built support for working hand in hand with MySQL; this doesn’t mean you can’t use PHP with other database management systems. You can still use PHP with
  • Postgres
  • Oracle
  • MS SQL Server
  • ODBC etc.

  What is PHP used for & Market share

  In terms of market share, there are over 20 million websites and application on the internet developed using PHP scripting language.

  This may be attributed to the points raised above;

  The diagram below shows some of the popular sites that use PHP

  

  PHP vs Asp.Net VS JSP VS CFML

  ASP – Active Server Pages, JSP – Java Server Pages, CFML – Cold Fusion Markup language The table below compares the various server side scripting languages with PHP

  FEATURE	PHP	ASP	JSP	CFML
  Learning curve	short	Longer than PHP	Longer than PHP	Longer than PHP
  Web hosting	Supported by almost all hosting servers	Needs dedicated server	Fairly supported	Needs dedicated server
  Open source	Yes	No	Yes	Both commercial and open source
  Web services support	Built in	Uses the .NET framework	Uses add on libraries	Built in
  Integration with HTML	Easy	Fairly complex	Fairly complex	Easy
  MySQL support	Native	Needs third party drivers	Needs third party drivers	Current version has native support. Older versions use ODBC
  Easily extended by other languages	Yes	No	Extended using Java classes and libraries.	Yes

  PHP File Extensions

  File extension and Tags In order for the server to identify our PHP files and scripts, we must save the file with the “.php” extension. Older PHP file extensions include

  PHP was designed to work with HTML, and as such, it can be embedded into the HTML code.

  

  You can create PHP files without any html tags and that is called Pure PHP file .

  The server interprets the PHP code and outputs the results as HTML code to the web browsers.

  In order for the server to identify the PHP code from the HTML code, we must always enclose the PHP code in PHP tags.

  A PHP tag starts with the less than symbol followed by the question mark and then the words “php”.

  PHP is a case sensitive language, “VAR” is not the same as “var”.

  The PHP tags themselves are not case-sensitive, but it is strongly recommended that we use lower case letter. The code below illustrates the above point.

  We will be referring to the PHP lines of code as statements. PHP statements end with a semi colon (;). If you only have one statement, you can omit the semi colon. If you have more than one statement, then you must end each line with a semi colon. For the sake of consistency, it is recommended that you always end your statement(s) with a semi colon. PHP scripts are executed on the server. The output is returned in form of HTML.

  PHP Hello world

  The program shown below is a basic PHP application that outputs the words “Hello World!” When viewed in a web browser.

  Summary

  • PHP stands for Hypertext pre-processor
  • PHP is a server side scripting language. This means that it is executed on the server. The client applications do not need to have PHP installed.
  • PHP files are saved with the “.php” file extension, and the PHP development code is enclosed in tags.
  • PHP is open source and cross platform

  Источник

  What is PHP?

  PHP (recursive acronym for PHP: Hypertext Preprocessor ) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML.

  Nice, but what does that mean? An example:

  Example #1 An introductory example

  Instead of lots of commands to output HTML (as seen in C or Perl), PHP pages contain HTML with embedded code that does «something» (in this case, output «Hi, I’m a PHP script!»). The PHP code is enclosed in special start and end processing instructions that allow you to jump into and out of «PHP mode.»

  What distinguishes PHP from something like client-side JavaScript is that the code is executed on the server, generating HTML which is then sent to the client. The client would receive the results of running that script, but would not know what the underlying code was. You can even configure your web server to process all your HTML files with PHP, and then there’s really no way that users can tell what you have up your sleeve.

  The best part about using PHP is that it is extremely simple for a newcomer, but offers many advanced features for a professional programmer. Don’t be afraid to read the long list of PHP’s features. You can jump in, in a short time, and start writing simple scripts in a few hours.

  Although PHP’s development is focused on server-side scripting, you can do much more with it. Read on, and see more in the What can PHP do? section, or go right to the introductory tutorial if you are only interested in web programming.

  User Contributed Notes

  Источник

  PHP Introduction

  Before you continue you should have a basic understanding of the following:

  If you want to study these subjects first, find the tutorials on our Home page.

  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 large social networks!
  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 is 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

  With PHP you are not limited to output HTML. You can output images or PDF files. 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

  What’s new in PHP 7

  • PHP 7 is much faster than the previous popular stable release (PHP 5.6)
  • PHP 7 has improved Error Handling
  • PHP 7 supports stricter Type Declarations for function arguments
  • PHP 7 supports new operators (like the spaceship operator: )

  Источник

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