PHP- Walk-In Interview Pune - softbridge Solutions

cURL Simple Example in PHP:


cURL allows you to connect and communicate to many different types of servers with many different types of protocols.
PHP Supports libcurl.

Example:

<?php
        // initialize curl session
        $ch = curl_init();
       
        curl_setopt($ch, CURLOPT_URL, "example.com");  // set url      
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);//return the transfer as a string
        
        $output = curl_exec($ch);//output string


        // close curl session
        curl_close($ch);     
?>

What is cURL in PHP?

cURL allows you to connect and communicate to many different types of servers with many different types of protocols.
PHP Supports libcurl.

Requirements:
In order to use PHP's cURL functions you need to install the libcurl package.PHP 5.0.0 requires a libcurl version 7.10.5 or greater.

cURL Functions:
    curl_close : Close a cURL session.
    curl_errno: Return the last error number.
    curl_error: Return a string containing the last error for the current session.
    curl_exec: Perform a cURL session.
    curl_getinfo: Get information regarding a specific transfer.
    curl_init: Initialize a cURL session.
    curl_setopt_array: Set multiple options for a cURL transfer.
    curl_setopt: Set an option for a cURL transfer.
    curl_version: Gets cURL version information.

Difference between Cookies and Session in PHP

• Cookies are stored in the user’s browser memory.A cookie can keep information in the user's browser until deleted.
• Session : logical object that allows you to preserve data across subsequent http requests.Whenever PHP creates a new session, it generates a session ID.
• Session values are store in server side not in user’s machine. A session is available as long as the browser is opened. User couldn't be disabled the session. 
• Cookies are stored in client side and sessions are stored in server side. 
• Cookies can only store strings.We could store not only strings but also objects in session.
• we could be save cookie for future reference, but session couldn't. When users close their browser, they also lost the session.

What is the difference between Get and post method.

How many ways you can delete a session variable?

1. unset($_SESSION["test"]);
2. session_destroy() — Destroys all data registered to a session
3. session_unregister() — Unregister a global variable from the current session.
4. session_unset() — Free all session variables.

To use the session variables again, session_start() has to be called.

Difference between array_slice() and array_splice() in php
array_splice() is used to remove some elements from an array and replace with specified elements.
array_slice() is used to extract a selected parts of an array .

array_slice() Function in PHP:

array_slice() is used to extract a selected parts of an array .

array_slice() Example:
<?php
$numbers = array("1", "2", "3", "4", "5");
$new_numbers = array_slice($numbers, 2);      
$new_numbers = array_slice($numbers, -3, 1);  
?>
Output:
Array
(
    [0] => 3
    [1] => 4
    [2] => 5
)
Array
(
    [0] => 3
    
)

How To Remove Html Tags From String In Php
In this article,I will explain how to remove Html tags from string with php.In php we are using strip_tags function to strip HTML and php tags.
strip_tags function returns a string with HTML and PHP tags stripped from a given string.

strip_tags Syntax:
strip_tags(string $string,string $allowable_tags);

Difference between include and include_once in php
All these functions include and include_once are used to include the files in the php page.


PHP include() Function:
If the specified file is not available ,the include() function generates a warning,and executes the
remaining code.

Example:
<?php 
include("test.php"); 
?>

Difference between php5 and php6
In this article, I will explain about upcoming changes in php6.php6 is not yet released.PHP6 will offer many improvements and will remove some of the functionality that has been in older versions of PHP.

Difference between php4 and php5 

PHP5 introduces many new features, I have mentioned some of them:

Unified Constructors and Destructors:
In PHP4, constructors had same name as the class name. In PHP5, you have to name your constructors as  __construct() and  destructors as __destruct().

Difference between mysql4 and mysql5 

MySQL 5 introduced new important features
1. Cursors
2. Triggers
3. Stored Procedures
4. Views

How to delete file in PHP:
In this article,I will explain how to delete file using php unlink function with sample example.

unlink: Deletes a file

difference between mysql_fetch_object and mysql_fetch_array in PHP

mysql_fetch_object :
mysql_fetch_object returns the results from database as objects.(fetches a result row as object)
$result->email

chdir function in php

The chdir() function changes the current directory to the other directory.

chdir() Syntax:
chdir(string $directory) 

chdir example:
<?php
getcwd();//current directory (e.g.c:\project)
chdir("files");//changes to files directory
echo $current_directory=getcwd();
?> 

Output: C:\project\files

Difference between join and implode in php. 
In this example, I will show how to use join and implode in php.

Join : Join is an Alias of implode().

Example:
<?php
$arr = array('Rajesh', 'India', 'Tutorials');
$str = join(",", $arr);
echo $str; 
?>
Output: Rajesh,India,Tutorials.

implode: implode Returns a string from array elements.

Example:
<?php
$arr = array('Rajesh', 'India', 'Tutorials');
$str = implode(",", $arr);
echo $str; 
?>
Output:Rajesh,India,Tutorials.

Check password length in php

I have written function to check password length in php

<?php
$password="checkpassword";


$passwordCheck=passwordLength($passwod);


function passwordLength($pwd)
{
    $pwdlen=strlen($pwd);//calculate length of password using strlen function


      if($pwdlen<=4) //if length of password is less than 4 then password is too short.
      {
         return "Password too short!";
      }
    else if ($pwdlen>16) //if length of password is greater than 16 then password is too Long.
   {
         return "Password too Long!";
     }
} 


?>

Regular expression Basics in php:
In this article ,i will show how to use regular expressions in php.

 \char escape char

  .            Any single character

 [chars]       One of following chars

 [^chars]      None of following chars

 text1|text2   text1 or text2

 ? 0 or 1 of the preceding text

 * 0 or N of the preceding text  (hungry)

 + 1 or N of the preceding text

 Example: (.+)\.html? matches test.htm and test.html

 (text)  Grouping of text

 Example:  ^(.*)\.html foo.php?bar=$1

  ^    Start of line anchor

  $    End   of line anchor

 Example: ^test(.*) matches test and test1 but not ttest
  (.*)1$ matches a1 and b1, but not test

.htaccess file and URL rewrite rule in php

Redirect URLs using .htaccess  :   
You can use .htaccess to redirect users to a different URL(redirect a url)    
Sometimes you need to redirect some URL and/or page on your site to another one.    
using the “Redirect” directive:    
   
Redirect /folder http://www.example.com/newfolder      
   
Another useful directive is the RedirectMatch    
   
RedirectMatch "\.html$" http://www.example.com/index.php      
   
This will redirect all requests to files that end with .html to the index.php file.      
One of the more powerful tricks of the .htaccess hacker is the ability to rewrite URLs    
   
simple rewriting        
all requests to whatever.htm will be sent to whatever.php:    
Options +FollowSymlinks      
RewriteEngine on      
RewriteRule ^(.*)\.htm$ $1.php [NC]      
RewriteRule ^menu.html menu.php      

Difference between strpos and stripos in php

strpos()Function in PHP:

strpos():Returns the position of the first occurrence of a substring in a string.
If the string is not found, this function returns FALSE.

Strpos Syntax:
strpos(string,search,start)

Strpos() function example in php:
<?php
$phpString = 'strpos function in php';
$search   = 'function';
$position = strpos($phpString, $search);


if ($position !== false)
{
     echo "Found at position $position";
}
 else
{
     echo "Not Found";
}
?>

stripos() Function in PHP:

The stripos() function is case-insensitive.
stripos():Returns the position of the first occurrence of a case-insensitive substring in a string.
If the string is not found, this function returns FALSE.

stripos Syntax:
stripos(string,search,start)

stripos () function example in php:
<?php
$phpString = 'strpos function in php';
$search   = 'Function';
$position = stripos($phpString, $search);


if ($position !== false)
{
     echo "Found at position $position";
}
 else
{
     echo "Not Found";
}
?>

Difference between strpos and stripos in php:

1. stripos works in php5, strpos in php4 and php5.
2. Unlike the strpos(), stripos() is case-insensitive.

Ob_start() function- Tutorials,Examples in Php5


ob_start Function is used to turn on output buffering.The PHP output buffering will save all the server outputs to a string variable.it  returns TRUE on success or FALSE on failure.
If you are using ob_start, then you should also use ob_end_flush  function for flushing the output buffer.

Ob_start() and ob_end_flush()  Example:

<?php
function changeColor($buffer)
{
  return (str_replace("Blue", "Red", $buffer));
}
//ob_start() function in PHP5
ob_start("changeColor");
?>
<html>
<tile>Ob_start() funtion Tutorials,Examples in Php5</title>
<body>
<span>Blue Car</span>
</body>
</html>
<?php
//ob_end_flush() function in PHP5
ob_end_flush();
?>
Output:
<html>
<tile>Ob_start() funtion Tutorials,Examples in Php5</title>
<body>
<span>Red Car</span>
</body>
</html>

Ob_start() and ob_get_clean()  Example:

<?php 
ob_start();
 ?>
<html>
<tile>Ob_start() funtion Tutorials,Examples in Php5</title>
<body>
<span>Blue Car</span>
</body>
</html>
<?php
 $code = ob_get_clean();
?>

Output:
<html>
<tile>Ob_start() funtion Tutorials,Examples in Php5</title>
<body>
<span>Blue Car</span>
</body>
</html>

How To Send Mail with Attachment in PHP
I this tutorial,I will explain how to send mail with attachments in PHP.

How to Send Email from a PHP Script using mail() function.

In this article, I will show you how to send  mail using PHP mail() function in PHP.

PHP mail() function:

The PHP mail() function is used to send emails in php.


Syntax :
mail(string to, string subject, string message, string headers,parameters);


to:  The receiver of the email
subject: The subject of the email.
message: the body of the email.
headers: Additional headers, like From, Cc, and Bcc.


Example:


<?php
$to = "rajesh@example.com";//The receiver of the email
$subject = "Test mail"; //The subject of the email.
$body = "Hello!"; //The body of the email.
$from = "test@example.com";
$headers = "From:" . $from; 
//mail() function
if(mail($to,$subject,$message,$headers)) 
{
   echo("Message successfully sent!");
}
else
{
  echo("Message delivery failed...");
}
?> 

PHP implode() Function

implode : The implode() function returns a string from the elements of an array.


Syntax
implode(separator,array)


Example: implode() 


<?php
$arr = array("PHP","implode","explode" ,"string","functions");
$str = implode(",", $arr);
echo $str; 
?>


Output: PHP, implode, explode, string, functions.

PHP explode() Function

explode :- The explode() function split a string into an array.

Syntax
explode(separator,string)


Note: Separator cannot be an empty string

Example: explode()

<?php


$name= "PHP implode explode string functions";
$arr = (" ", $name);
print_r($arr);
?>


Output:
array([0]=>"PHP",[1]=>"implode",[2]=>"explode",[3]=>"string",[4]=>"functions");

Let us begin with a very simple PHP program. 

Example:

hello.php
<?php
echo "Hello!!.";
?>
Output:Hello!!.


Example Using HTML and PHP
hello.php


<html> 
<head><title>My First PHP Page</title></head> 
<body> 
<span>
<?php 
   $name="Rajesh";
   echo "Hello $name";
?>
</span> 
</body> 
</html> 


Output:Hello Rajesh

Difference between strstr and stristr in php.

strstr() and stristr both are used to find the first occurence of the string but stristr( ) is case insensitive.

strstr() - Find first occurrence of a string
Syntax:
strstr ($string, string)  

Example:

<?php
$email = 'rajesh@tEst.com';
$domain_name = strstr($email, 'E');
echo $domain_name; 


?>


Output:Est.com

stristr() - Find first occurrence of a string (Case-insensitive)
Syntax:
stristr ($string, string)  

Example:
<?php
$email = 'rajesh@tEst.com';
$domain_name = stristr($email, 'E');
echo $domain_name; 


?>
Output: esh@tEst.com

A .htaccess rule that will divert any page in another folder


1)If you want to redirect http://test.com/f1/  to  http://test.com/f2/.
 .htaccess file will be.

Options +FollowSymLinks
RewriteEngine On
RewriteRule ^f1.*$ http://test.com/f2/ [R=301,L]


2)If you want to redirect http://test.com/f1/test.html to http://test.com/f2/test.html.
 .htaccess file will be.

Options +FollowSymLinks
RewriteEngine On
RewriteRule RewriteRule ^f1/(.*)$ http://test.com/f2/$1 [R=301,L]

3) If you want to redirect http://test.com/ to http://www.test.com/.
 .htaccess file will be.


Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^test.com [NC]
RewriteRule ^(.*)$ http://www.test.com/$1 [R=301,L]

4) If you want to redirect  http://test.com/ to https://test.com/.

 .htaccess file will be.
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.test.com/$1 [R,L]

urlencode :-Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs.

Syntax:
string urlencode ( string $str );

Example:
<?php
$url="Rajesh SharmaTutorials";
$encodeUrl=urlencode($url);
echo '<a href="test.php?sample=$encodeUrl">';
?>

Output: <a href="test.php?sample=Rajesh+Sharma+Tutorials">

urldecode :- Returns the decoded string.(Returns the original string of the input URL).

<?php
$sample=$_GET["sample"];
 echo $sample=urldecode($sample);
?>

Output:Rajesh SharmaTutorials

persistent cookie in php:

A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer.

• Content of a Persistent cookie remains unchanged even when the browser is closed.
• Persistent cookies are less secure because users can open cookie files see the cookie values.
• Persistent cookies can be used for tracking long-term information. 

Setting cookie in php:
Cookies in PHP can be set using the setcookie() function

Syntax:
Setcookie(name, value, expire, path, domain);

Example:
<?php
Setcookie(“Full Name”, “Rajesh Sharma”, time()+3600);
?>

Polymorphism in OOP:

In this tutorial we will study about polymorphism.

• Polymorphism in PHP5 : To allow a class member to perform diffrent tasks.
• polymorphism where the function to be called is detected based on the class object calling it at runtime.

Example:
< ?
class Person
{
    public function Talk()
    {
         echo "English";
    }
}

class Language extends Person
{
      public function Talk()
      {
           echo "French";
      }


}

function CallMethod(Person $p)
{
      $p->Talk();
}



$l = new Language();
CallMethod($l);
?>


Output:
French;

Inheritance in OOP :

In this tutorial we will study about Inheritance.

• Inheritance is a mechanism of extending an existing class.
• In Inheritance child class inherits all the functionality of Parent Class.

For example, when you extend a class, the subclass inherits all of the public and protected methods from the parent class. Unless a class overrides those methods.

<?php


class BaseClass
{
    public function GetValue($string)
    {
        echo 'BaseClass:'. $string ;
    }


    public function setValue($string)
    {
        echo  $string;
    }


    
}


class ChildClass extends BaseClass
{
    public function GetValue($string)
    {
        echo 'ChildClass:'. $string ;
    }
}


$b = new BaseClass();
$c = new ChildClass();


$b->GetValue('Rajesh Test'); // Output: 'BaseClass: Rajesh Test'
$b->setValue('Rajesh Test'); // Output: 'Rajesh Test'
$c->GetValue('Rajesh Tutorials'); // Output:'ChildClass: Rajesh Tutorials'
$c->setValue('Rajesh Test'); // Output: 'Rajesh Test'


?>

Serialization/UnSerialization:

• Generates a storable representation of a value.
• serialize() returns a string containing a byte-stream representation of any value that can be stored in PHP. 
• unserialize() can use this string to recreate the original variable values.
• This process makes a storable representation of a value that is useful for storing or passing PHP values.
• To make the serialized string into a PHP value again, use unserialize().

Before starting your serialization process, PHP will execute the __sleep function automatically. This is a magic function or method.
Before starting your unserialization process, PHP will execute the __wakeup function automatically. This is a magic function or method.


What can you Serialize and Unserialize?

• Variables
• Arrays
• Objects 

What cannot you Serialize and Unserialize?

• Resource-type

Example:
//BaseClass.php
<?php

  class BaseClass {
      public $var = 100;
    
      public function show() {
          echo $this->var;
      }
  }
  
// test1.php:


  include("BaseClass.php");
  
  $a = new A;
  $v = serialize($a);
  file_put_contents('store_in_var', $v);


// page2.php:
  
  include("BaseClass.php");
  $v = file_get_contents('store_in_var');
  $a = unserialize($v);




  $a->show();
?>

In the Case if you want to store entire array into database then with serialze() it would be useful to store an entire array in a field in a database.
You can pass an array to the function, and it will return a string that is essentially the string. 
You can then unserialize() it to obtain the full array once again.


example:


<?php

$str_array = array( "Rajesh Sharma", "Rajesh", "RajeshS" );
$serialized_str = serialize($str_array);
echo $serialized_str;


?>


This will output a:3:{i:0;s:14:"Rajesh Sharma";i:1;s:6:"Rajesh";i:2;s:7:"RajeshS";}
so you can store entire array in a field in a database.

Access modifier:
OOP provides data-hiding capabilities with public, protected, and private data attributes and methods:


Public : A public variable or method can be accessed directly by any user of the class.


Protected : A protected variable or method cannot be accessed by users of the class but can be accessed inside a subclass that inherits from the class.


Private:A private variable or method can only be accessed internally from the class in which it is defined.

Constructor:


PHP 5 allows developers to declare constructor methods for classes.Classes call constructor method on each newly-created object. 
function __construct() {
//
}
Example:


<?php
class MainClass {
   function __construct() {
      echo "In MainClass constructor\n";
   }
}


class ChildClass extends MainClass {
   function __construct() {
       parent::__construct();
      echo "In SubClass constructor\n";
   }
}


$obj = new MainClass();
$obj = new SubClass();
?>
Note: If  PHP 5 cannot find a __construct() function for a given class, it will search for the old constructor function, by the name of the class. 


Destructor:


The destructor method will be called as soon as Classes destroy the object.


 function __destruct() {
  //     
   }
Example:


<?php
class MainClass {
   function __construct() {
      echo "In MainClass constructor\n";
   }
function __destruct() {
       print "Destroying \n";
   }
}
class ChildClass extends MainClass {
   function __construct() {
       parent::__construct();
      echo "In SubClass constructor\n";
   }
   
}


$obj = new MainClass();
$obj = new SubClass();
?>


Note:The destructor method will be called even if script execution is stopped using exit().

Static Methods and Properties:


In this Article,I will explain how to use  Static properties or methods in PHP5.

• To implement static keyword functionality to the attributes or the methods will have to be prefix with static keyword.
• Static properties or methods can be accessible without needing an instantiation of the class.
• A property declared as static can not be accessed with an instantiated class object.
• $this is not available inside the method declared as static.
• Static properties cannot be accessed using the arrow operator ->. 
• Static properties can be accessed using the Scope Resolution Operator (::) operator.

                                                  ClassName::$staticvar= $value;


Example:

<?php 
class Box
{
   static private $color;  
   function __construct($value)
   {
  if($value != "")
  {
   Box::$color = $value; 
  }
  $this->getColor();
   }
   public function getColor()
   {
  echo Box::$color ;
   }
    
   static public function StaticMethod() {


        echo self::$color;


    }


}
$a = new Box("RED");
Box::StaticMethod();
$a = new Box("GREEN");
$a = new Box("");
?>


OUTPUT:
RED
RED 
GREEN
GREEN

Static Keyword:


In this Article,I will explain how to use Static Keyword in PHP5.

• To implement static keyword functionality to the attributes or the methods will have to be prefix with static keyword.
• Static properties or methods can be accessible without needing an instantiation of the class.
• A property declared as static can not be accessed with an instantiated class object.
• $this is not available inside the method declared as static.
• Static properties cannot be accessed using the arrow operator ->. 
• Static properties can be accessed using the Scope Resolution Operator (::) operator.

                                                  ClassName::$staticvar= $value;

Example:


<?php
class Box
{
   static private $color;  

   function __construct($value)
   {
if($value != "")
{
Box::$color = $value; 
}
$this->getColor();
   }

   public function  getColor ()
   {
echo Box::$color;
   }
}

$a = new Box("RED");
$a = new Box("GREEN");
$a = new Box("");
?>

OUTPUT:
RED
GREEN
GREEN

Abstract Class:

• To define a class as Abstract, the keyword abstract is to be used. 
• In abstract class at least one method must be abstract.
• we can create object of abstract class.
• abstract classes may not be instantiated.
• The child classes which inherits the property of abstract base class, must define all the methods declared as abstract.
• Any class that contains at least one abstract method must also be abstract.
• If the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private.
• Abstract class can contain variables and concrete methods.
• A class can Inherit only one Abstract class and Multiple inheritance is not possible for Abstract class.

Abstract Class:


To define a class as Abstract, the keyword abstract is to be used e.g. abstract class ClassName { }

• In abstract class at least one method must be abstract.
• we can create object of abstract class.
• Abstract classes may not be instantiated.
• The child classes which inherits the property of abstract base class, must define all the methods declared as abstract.
• Any class that contains at least one abstract method must also be abstract.
• If the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private.
• Abstract class can contain variables and concrete methods.
• A class can Inherit only one Abstract class and Multiple inheritance is not possible for Abstract class.

Example:


<?php
abstract class AbstractClass
{
    abstract protected function getValue();
    abstract protected function setValue($val);


    public function Display() {
        print $this->getValue() . "\n";
    }
}


class ChildClass1 extends AbstractClass
{
    protected function getValue() {
        return "ChildClass1";
    }


    public function setValue($val) {
        return "ChildClass{$val}";
    }
}


class ChildClass2 extends AbstractClass
{
    public function getValue() {
        return "ChildClass2";
    }


    public function setValue($val) {
        return "ChildClass{$val}";
    }
}


$class1 = new ChildClass1;
$class1->Display();
echo "<br>";
echo $class1->setValue('1') ."\n";
echo "<br>";
$class2 = new ChildClass2;
$class2->Display();
echo "<br>";
echo $class2->setValue('2') ."\n";
?>

Interfaces:

• In interface all the method must be abstract(only define).
• All methods declared in an interface must be public.
• Interfaces cannot contain variables and concrete methods except constants.
• A class can implement many interfaces and Multiple interface inheritance is possible.
• To extend from an Interface, keyword implements is used.

Example:


interface Shape
 {
function getShape();
}

class Circle implements Shape{
public function getShape() {
return "This is Shape of the Circle\n";
}
}

class MultiInher {
public function read(Shape $s) {
$shape = $s->getShape();
//
echo $shape;
}
}

$c = new Circle();

$m = new MultiInher();
$m->read($c);

Encapsulation:
The wrapping of data and function together in a single unit(class) is called encapsulation.
In PHP 4 objects were little more than arrays.In PHP 5 you get much more control by visibility, 
interfaces,and more.


PHP5 provides data-hiding capabilities with public, protected, and private data attributes and methods:


Public : A public variable or method can be accessed directly by any user of the class.


Protected : A protected variable or method cannot be accessed by users of the class but can be accessed inside a subclass that inherits from the class.


Private: private variable or method can only be accessed internally from the class in which it is defined.


E.g.:
class is a protective wrapper which binds data and methods together,they can be accessed only though object of that class.


Example:


<?php 


class Shape { 


     private static $_circle; 


     public function Circle( ) { 
          if( $this->_circle == null ) { 
               $this->_circle = new Circle(); 
          } 
          return $this->_circle; 
     } 


} 


class Circle { 


     private $_radius; 


     public function __construct() { 
          $this->_radius = "10"; 
     } 


     public function GetRadius() { 
          return $this->_radius; 
     } 
} 


$shape= new Shape(); 


echo $shape->Circle()->GetRadius(); 
?>

In this tutorial ,I will explain about abstract class in PHP, how to declare and use of an abstract class.

Abstract Class:
It may contain one or more abstract methods.abstract classes may not be instantiated.The child classes which inherits the property of abstract base class, must define all the methods declared as abstract.
Any class that contains at least one abstract method must also be abstract.
if the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private.

This article shows you how to add/delete rows to an HTML table dynamically, using DHTML and JavaScript.The code has been tested to work with Firefox . It may work with other browsers.The sample code has two JavaScript functions - one to add new rows and the other to delete rows.
Example:


<HTML>
<HEAD>
    <TITLE> Add/Remove dynamic rows in HTML table </TITLE>
    <SCRIPT language="javascript">
        function addRow(table_Id) {

            var table = document.getElementById(table_Id);

            var rowCnt = table.rows.length;
            var row = table.insertRow(rowCnt);

            var RowCell1 = row.insertCell(0);
            var e = document.createElement("input");
            e.type = "checkbox";
            RowCell1.appendChild(e);

            var RowCell2 = row.insertCell(1);
            RowCell2.innerHTML = rowCnt + 1;

            var RowCell3 = row.insertCell(2);
            var e2 = document.createElement("input");
            e2.type = "text";
            RowCell3.appendChild(e2);

        }

        function deleteRow(table_Id) {
            try {
            var table = document.getElementById(table_Id);
            var rowCnt = table.rows.length;

            for(var i=0; i<rowCnt; i++) {
                var row = table.rows[i];
var selected_chkbox = row.cells[0].childNodes[0];
                if(null != selected_chkbox && true == selected_chkbox.checked) {
                    table.deleteRow(i);
                    rowCnt--;
                    i--;
               
 }
            }
            }catch(e) {
                alert(e);
            }
        }

    </SCRIPT>
</HEAD>
<BODY>
     <TABLE id="table_Id"  border="1">
        <TR>
            <TD><INPUT type="checkbox" name="chekbx"/></TD>
            <TD> 1 </TD>
            <TD> <INPUT type="text" /> </TD>
        </TR>
    </TABLE>
<INPUT type="button" value="ADD ROW" onclick="addRow('table_Id')" />
<INPUT type="button" value="DELETE ROW" onclick="deleteRow('table_Id')" />

</BODY>
</HTML>

Properties of Object Oriented Systems:

• support inheritance
• provides encapsulation of data
• provides extensibility of existing data types and classes
• provide support for complex data types
• Inheritance-one class inherite the property of another class..
• Aggregation-.is a part whole relationship.
• Association.:is a relationship between 1 or more instances of a class.

            public class cars
            {
                  //
            }


               cars object_car = new cars();
ClassName objectName=new ClassName();
          Car objCar= new Car();