Introduction to PHP from Beginning to End

ChristopherY. Sabado, Mst-CS
Assistant Professor 2
Program Chairperson, BSInfoTech
What is PHP? Write your first PHP Program

What is PHP?
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”.

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.

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.

A PHP file can also contain tags such as HTML and client
side scripts such as JavaScript.
HTML is 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 asASP 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 File Extensions
File extension andTags 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
• .phtml
• .php3
• .php4
• .php5
• .phps
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 “HelloWorld!”When viewed in a web browser.

Steps in Saving your PHP file:
Step 1: Make a folder inside C:xampphtdocs
In my example I named my folder lessons,
you follow the same name.
Step 2: In your text editor, click File, then SaveAs,

Step 3: Locate the folder you have just name in my case the Lessons Folder.
Step 4:You must make sure you are inside the HTDOCS folder and inside
the folder you have just made.
Step 5: In the filename section, write the filename Hello.php
Step 6: Click Save.
,

How to run your first PHP Program:
Step 1: Open XAMPP Control Panel
Step 2: Click Start opposite to Apache. In should turn from START to now
STOP and Apache now color Green.
Step 3: Click Close or X

Step 4: Open your web browser (we prefer Google Chrome)
Step 5:Type the following in the URL section:
Take note, you need to replace the lessons word with the name of
your folder that you have created.
Step 6: Press ENTER to display the output.

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

<?php
$x = 5985;
var_dump($x);
?>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$y = 6;
echo $x + $y;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$y = 6;
echo $x - $y;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$y = 6;
echo $x * $y;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$y = 6;
echo $x / $y;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$y = 3;
echo $x ** $y;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 20;
$x += 100;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 50;
$x -= 30;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 5;
$x *= 6;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 10;
$x /= 5;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 15;
$x %= 4;
echo $x;
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 100;
$y = "100";
var_dump($x == $y); // returns
true because values are equal
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 100;
$y = "100";
var_dump($x === $y); //
returns false because types are not
equal
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 100;
$y = "100";
// returns false because values
are equal
var_dump($x != $y);
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 100;
$y = "100";
var_dump($x <> $y); // returns
false because values are equal
?>
</body>
</html>

<!DOCTYPE html>
<html>
<bodya>
<?php
$x = 100;
$y = "100";
var_dump($x !== $y); //
returns true because types are not
equal
?>
</body>
</html>

<!DOCTYPE html>
<html>
<body>
<?php
$x = 100;
$y = 50;
var_dump($x > $y); // returns true because $x is
greater than $y
?>
</body>
</html>

Introduction to PHP from Beginning to End

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