Lesson-5-php BY AAFREEN SHAIKH.pdf HSC INFORMATION TECHNOLOGY CHAP 5 PHP

From:
MISS AAFREEN SHAIKH (IT Teacher)
CHHATRAPATI SHIVAJI JR SCI
COLLEGE JALGAON
5. SERVER SIDE SCRIPTING (PHP)
AAFREEN SHAIKH
Index:
Features of PHP
PHP variables, datatypes
PHP Array, String function and user- defined
functions
PHP form handling
•PHP connectivity with database server
1

➢ PHP stands for Hypertext Preprocessor.
➢ It is widely used open source general purpose server- side scripting language.
➢ It is widely used for web development and can be embedded with HTML.
➢ PHP scripts are executed on the server.
➢ PHP is free to download and use.
➢ PHP runs on various platform like LINUX, UNIX, Mac OS, Windows etc.
➢ It is compatible for almost all servers used today like XAMMP, Apache, NGINX, lighttpd.
➢ It supports wide range of databases.
➢ PHP is easy to learn and runs efficiently on the server side.
➢ PHP is free to download and one can download it from the official website www.php.net
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➢ A server is a computer system that serves as a central repository of data and programs and is shared
by all clients.
➢The server side environment that runs a scripting language is termed as web server.
➢Server-side scripting as it relates to web pages usually refers to PHP code that is executed on the web
server before the data is passed to the user's browser.
➢In the case of PHP, all PHP code is executed server-side and no PHP code ever reaches the user.
➢ After the PHP code is executed, the information it outputs is embedded in the HTML, which is sent to
the viewer's web browser.
➢ It is usually used to provide interactive web sites that interfaces with databases or other data stores on
the server.
➢ Few server-side scripting languages are PHP, Java & JSP, Python.
➢PHP mainly focuses on server-side scripting , which is used to collect form data, generate dynamic page
content or send and receive cookies
AAFREEN SHAIKH

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Simple: It is very simple and easy to use as compared to other scripting languages.
Interpreted: It is an interpreted language i.e no need of compilation.
Faster: It is faster than other scripting language e.g JSP & ASP
Open Source: It means you will not pay money to use it .You can freely download and use it.
Platform Independent: It will run on all platform like Linux, Unix, Mac OS, Windows.
Case Sensitive: It is case sensitive when you declare variables.
All keywords(echo , if, else etc) ,classes, functions and user-defined functions are not case-
sensitive.
Error Reporting: PHP has some pre-defined error reporting constants to generate a warning
or error notice.
Real Time Monitoring: PHP provides access logging by creating summary of recent accesses
for the user.
Loosely Typed Language: PHP allows you to use variable without declaring its data type. It
will be taken at the time of execution , based on the type, data has its value.
AAFREEN SHAIKH

5
• A php file normally contains HTML tags and some PHP scripting code.
• PHP Script usually enclosed in special start and end tag processing instructions.
<?php …. ?> which allows us to move into and out of php mode.
• A PHP script start with <?php and ends with ?>
Ex- <? Php
PHP program code goes here
?>
• Even it allows to embed HTML with PHP.
• Extension of php is”.php”
• PHP script can be placed anywhere in HTML document.
• echo is used to display text on web page.
AAFREEN SHAIKH

PHP CASE SENSITIVITY
➢In PHP “Variables names ”are case sensitive.
➢However keywords(ex. If,else,break,for,while,echo), functions,
class name are not case sensitive.
➢The “ECHO” keyword is Case insensitive.
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Go to the browser and type http://localhost/first.php
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First.php
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•Variable is a symbol or name that stands for a value.
•Variables are used for storing values such as numeric, characters, strings or
memory addresses, so that they can be used in any part of program.
RULES FOR DECLARING VARIABLES
•Variable starts with $ sign, followed by name of the variable.
•A variable name must start with a letter or underscore character.
• A variable name cannot start with a number.
• A variable name can only contain alpha-numeric characters and underscores(A-
z,0-9 and _[underscore]) .
•Variable names are case-sensitive. (Eg. $age and $AGE are considered different).
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AAFREEN SHAIKH

🞂 Program using PHP
variables
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<!DOCTYPE html>
<html>
<body>
<?php
$txt = "Hello world!";
$x = 5;
echo $txt;
echo "<br>";
echo $x;
?>
</body>
</html>
OUTPUT
Hello world!
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AAFREEN SHAIKH

SCOPE OF VARIABLES IN PHP
•Local: A variable declared within a function has local scope and can be accessed
within that function.
• Global: A variable declared outside the function has a global scope and can only
be accessed outside the function.
•Static: When a function is executed , then all of its variables are deleted. If you
want a local variable not to be deleted then use must use static keyword.
Comments
Comments :-are not visible in the output of the program as it is ignored during
the execution.
A single line comments is given by // or # before the PHP statement and a
multi-line comment is possible by /*…*/
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AAFREEN SHAIKH

PIMPRI CHINCHWAD EDUCATION TRUST’S
S.B.PATIL COLLEGE OF
Science and Commerce, Ravet
PHP DATA TYPES
PHP can store data of different types and PHP supports following data types:
•String
•Integer
•Float
•Boolean
•Array
•NULL
•One can check the data_type of variable using var_dump() method in PHP.
•var_dump() gives different output for each data_type.
➢It gives length of the string for “string”
data_type.
➢It gives actual value of integer for “integer”
data_type.
➢It gives true/false for “boolean” data_type
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AAFREEN SHAIKH

CONTROL STRUCTURES IN PHP
If STATEMENT : if STATEMENT ALLOWS PROGRAMMER to MAKE decision, BASED on one or
more conditions; AND execute A piece of code CONDITIONALLY.
SYNTAX :
if(condition)
{
block of statement;
}
2. If-else statement: if-else statement allows programmer to make decision based
on either this or that conditions.
Syntax: if(condition)
{
statement;
}
else
{
statement
}
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AAFREEN SHAIKH

CONTROL STRUCTURES IN PHP
<!DOCTYPE html>
<html>
<body>
<?php
$t=10;
if ($t < "20")
{
echo "LESS THAN 20 !";
}
?>
</body>
</html>
OUTPUT
LESS THAN 20 !
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IF - ELSE
SIMPLE IF
AAFREEN SHAIKH

and loop iteration (increment or decrement) in single
combines initialization, condition
statement.
Syntax :
for(initialisation;condition;increment/decrement)
{
Statement;
}
for…….loop
Loops are used to execute the same block of code repeatedly as long as a certain condition is
satisfied.
This loop executes statements as long as condition becomes true, for-loop is that it
code to be executed
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AAFREEN SHAIKH

foreach…….loop
foreach loop: This loop work only on arrays, and is used to loop through each key/value pair in
array. For every loop iteration, the value of the current array element is assigned to
$value and the array pointer is moved by one, until it reaches the last array element.
NOTE: (.) is used for concatenation purp
Syntax: foreach($array as $value)
{
code to be executed;
}
ose.
Output
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AAFREEN SHAIKH

foreach…….loop
Output
<?php
$array1 = array(1, 2, 3, 4, 6, 22, 32, 12, 11, 14, 16, 17, 18, 19, 28);
foreach ($array1 as $value1) {
$value1 = $value1 * 2;
echo $value1.", ";
}
?>
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AAFREEN SHAIKH

PHP STRING FUNCTION
•A string is series of character.
•The real power of PHP comes from its functions.
•A function is block of statement used repeatedly in a program.
•PHP has many built-in functions which can be called directly to perform a
specific task.
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AAFREEN SHAIKH

PHP ARRAY
• An array is a special variable which can hold more than a value at a time.
•An array stores multiple values in one single variable.
• The index can be assigned automatically.(index always starts with 0)
Syntax: $array_name=array(value1,value2,……., value n)
$cars
= array("Volvo", "BMW", "Toyota");
$cars[0]= Volvo
$cars[1]= BMW
$cars[2]= Toyota
• There are 3 types of arrays
•Indexed arrays - Arrays with a numeric index
•Associative arrays - Arrays with named keys
•Multidimensional arrays - Arrays containing one or more arrays
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AAFREEN SHAIKH

➢In this example , we store subject is an
array at following index location.
$subject[0]=“English”
$subject[1]=“Hindi”
$subject[2]=“Marathi”
count() function is used to return the Length of
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array
AAFREEN SHAIKH

•A function is block of statement used repeatedly in a program.
•It will not execute immediately when a page loads but will be executed by a
call to the function.
•Along with built-in PHP functions we can create our own functions.
•User-defined function starts with the word function.
• Information can be passed to functions through arguments.
•An argument is just a variable.
•Arguments are specified after the function name, inside brackets.
Syntax: function fun_name()
{
code to be executed
}
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Note : 'language' attribute of <Script> is replaced by 'type' attribute in all the programs as it is standardized.
Use return statement to return a value.
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PHP ASSOCIATIVE ARRAYS :
ASSOCIATIVE ARRAYS ARE ARRAYS THAT use NAMED keys INSTEAD of index to
identify RECORD/VALUE.
Let us see how to CREATE ASSOCIATIVE ARRAY.
SYNTAX :
$a = array( key1 => value1, key2=>value2, ...,key n => value n)
VALUES of ‘STUDENT_MARK’ ARRAY ARE
stored in following WAY:
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AAFREEN SHAIKH

When to use GET?
➢Information send from a form using GET method is visible to everyone.(names
and values of variables are displayed on URL)
➢ It also has limit on amount of information to send. Because the variables are
displayed in the URL ,it is possible to bookmark the page.
➢It may be used to send some non-sensitive data.
➢ It should never be used to for sending passwords or other sensitive
information.
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AAFREEN SHAIKH

Let us see one program on “get” method
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When to use POST?
➢Information send from a form using POST method is invisible to
everyone.(all names and values are embedded within the body of the
HTTP request.)
➢ It has no limit on amount of information to send.
➢Moreover POST supports advanced functionality such as support
for multi-part binary input while uploading files to the server.
➢ The variables are not passed in the URL so it is possible to
bookmark the page.
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AAFREEN SHAIKH

Note : 'language' attribute of <Script> is replaced by 'type' attribute in all the programs as it is standardized.
A simple HTML form with 2 input fields and submit button code is as
follows:
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➢When user fills out the form above and clicks
the submit button , the form data is sent for
processing to a PHP file names “welcome
.php”.
➢The form data is sent with the HTTP POST
method.
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➢ The code for “welcome.php” looks like this
AAFREEN SHAIKH

•Both GET and POST are treated as $_GET and $_POST super globals,
which means they are accessible ,regardless of scope.
•It can be accessed from function ,class or file without having to do
anything special.
•$_GET is an array of variables passed via the URL parameters.
•$_POST is an array of variables passed via the HTTP POST method.
GET vs POST
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AAFREEN SHAIKH

Summary
PHP is widely-used open source server-side programming language which runs on
various platforms.
PHP is a script executed on server which generate dynamic HTML pages.
The PHP code can also be embedded with HTML tags using <?php and ?>.
PHP is case sensitive only at time of variable declaration and not-case sensitive for
other keywords.
PHP variable start with $ sign followed by name of variable which must start with a
alpha-numeric characters or underscore character.
PHP variable has three different scopes namely : local, global and static.
PHP supports String, Integer, Float, Boolean, Array and NULL data types.
Three types of Arrays are Indexed array, Associative array and Multi-dimensional
array.
PHP supports ‘foreach’ loop to iterate easily.
String functions are used to manipulate strings.
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AAFREEN SHAIKH

Summary
A function is a block of statements that can be used repeatedly in a program.
Information can be passed to functions through arguments.
Form is used to collect information from user and process or store in database.
Form data can be submitted by GET or POST method.
The PHP superglobals $_GET and $_POST are used to collect form-data.
$_GET is an array of variables passed via the URL parameters and are visible to
everyone.
$_POST is an array of variables passed via the HTTP POST method and are
invisible to others.
GET has limits on the amount of information to send whereas POST has no limits
on the amount of information to send.
GET should NEVER be used for sending sensitive information.
Cookies are sent along when browser requests server pages.
Session helps web application to maintain user information on all the pages.
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AAFREEN SHAIKH

Lesson-5-php BY AAFREEN SHAIKH.pdf HSC INFORMATION TECHNOLOGY CHAP 5 PHP

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