ajax

AJAX

AJAX = Asynchronous JavaScript and XML.

AJAX is a technique for creating fast and dynamic web pages.

AJAX allows web pages to be updated asynchronously by exchanging small amounts of data with the server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

ASP.NET 2.0 AJAX

On June 28, 2005, Microsoft announced “ASP.NET 2.0 AJAX.” ASP.NET 2.0 AJAX is an AJAX-oriented .NET library that runs on .NET 2.0. Though ASP.NET 2.0 AJAX is an AJAX library and can be used to perform AJAX operations, it is really much more. ASP.NET 2.0 AJAX offers many of the same types of features of the server-side ASP.NET, but it is directed at the client side. Because ASP.NET 2.0 AJAX is fully integrated with ASP.NET, it provides rich integration with the services provided by ASP.NET.

ASP.NET 2.0 AJAX provides the following features (and much more):

•AJAX-style communications between client and server. This communication is over web services.

•Asynchronous communication. All client-to-server communication in the ASP.NET 2.0 AJAX framework is asynchronous.

•A set of server-side controls that enable rich client-side functionality.

•A set of client-side controls and classes that further enable client-side functionality.

•A framework for encapsulating client-logic through the creation of namespaces and classes.

•Cross browser support. Although there is no official matrix of web browsers that ASP.NET 2.0 AJAX supports, the latest versions of Internet Explorer, Firefox, and Safari are supported. In addition, Opera is thought to be supported; however, we have not been able to find an official statement from Microsoft regarding this.

 Disadvantage of AJAX-

•Search engines would not be able to index an AJAX application.

•The server information can not be accessed within AJAX.

•AJAX is not well integrated with any browser.

•ActiveX requests are enabled only in IE 5 and IE6

•Data of all requests is URL-encoded, which increases the size of the request.

php interview question

Q : 1	Who is the father of PHP ?
Answers :	Rasmus Lerdorf is known as the father of PHP.
Q : 2	What is the difference between $name and $$name?
$name is variable where as $$name is reference variable like $name=sonia and $$name=singh so $sonia value is singh.
Q : 2	What will be the output of the following: Example 1# <?php echo 1>2; <? Example 2# <?php echo 2>1; <?
Example #1 will produce no output Example #1 will produce no output: 1
Q : 2	What is the difference between registering a session variable using $_SESSION and session_register('variable_name').
	# $_SESSION session_register('variable_name'). 1 We need to call explicitly session_start() to start a session It implicitly call session_start() 2 It return type is a string It returns a boolean vale true or false
Q : 2	What is the difference between copy and move_uploaded_file functions.
Q : 3	How can we submit a form without a submit button?
Java script submit() function is used for submit form without submit button on click call document.formname.submit()
Q : 4	In how many ways we can retrieve the data in the result set of MySQL using PHP?
Answer : 4	We can do it by 4 Ways 1. mysql_fetch_row. , 2. mysql_fetch_array , 3. mysql_fetch_object 4. mysql_fetch_assoc
Q : 5	What is the difference between mysql_fetch_object and mysql_fetch_array?
Answers : 5	mysql_fetch_object() is similar tomysql_fetch_array(), with one difference - an object is returned, instead of an array. Indirectly, that means that you can only access the data by the field names, and not by their offsets (numbers are illegal property names).
Q : 6	What are the differences between Get and post methods.
Answers : 6	There are some defference between GET and POST method 1. GET Method have some limit like only 2Kb data able to send for request But in POST method unlimited data can we send 2. when we use GET method requested data show in url but Not in POST method so POST method is good for send sensetive request
Q : 7	How can we extract string "pcds.co.in " from a string "http://info@pcds.co.in using regular expression of PHP?
Answers : 7	preg_match("/^http:\/\/.+@(.+)$/","http://info@pcds.co.in",$matches); echo $matches[1];
Q : 8	How can we create a database using PHP and MySQL?
Answers : 8	We can create MySQL database with the use of mysql_create_db("Database Name")
Q : 9	What are the differences between require and include?
Answers : 9	Both include and require used to include a file but when included file not found Include send Warning where as Require send Fatal Error .
Q : 10	Can we use include ("xyz.PHP") two times in a PHP page "index.PHP"?
Answers : 10	Yes we can use include("xyz.php") more than one time in any page. but it create a prob when xyz.php file contain some funtions declaration then error will come for already declared function in this file else not a prob like if you want to show same content two time in page then must incude it two time not a prob
Q : 11	What are the different tables(Engine) present in MySQL, which one is default?
Answers : 11	Following tables (Storage Engine) we can create 1. MyISAM(The default storage engine IN MYSQL Each MyISAM table is stored on disk in three files. The files have names that begin with the table name and have an extension to indicate the file type. An .frm file stores the table format. The data file has an .MYD (MYData) extension. The index file has an .MYI (MYIndex) extension. ) 2. InnoDB(InnoDB is a transaction-safe (ACID compliant) storage engine for MySQL that has commit, rollback, and crash-recovery capabilities to protect user data.) 3. Merge 4. Heap (MEMORY)(The MEMORY storage engine creates tables with contents that are stored in memory. Formerly, these were known as HEAP tables. MEMORY is the preferred term, although HEAP remains supported for backward compatibility. ) 5. BDB (BerkeleyDB)(Sleepycat Software has provided MySQL with the Berkeley DB transactional storage engine. This storage engine typically is called BDB for short. BDB tables may have a greater chance of surviving crashes and are also capable of COMMIT and ROLLBACK operations on transactions) 6. EXAMPLE 7. FEDERATED (It is a storage engine that accesses data in tables of remote databases rather than in local tables. ) 8. ARCHIVE (The ARCHIVE storage engine is used for storing large amounts of data without indexes in a very small footprint. ) 9. CSV (The CSV storage engine stores data in text files using comma-separated values format.) 10. BLACKHOLE (The BLACKHOLE storage engine acts as a "black hole" that accepts data but throws it away and does not store it. Retrievals always return an empty result)
Q : 12	What is use of header() function in php ?
Answers : 12	The header() function sends a raw HTTP header to a client.We can use herder() function for redirection of pages. It is important to notice that header() must be called before any actual output is seen..
Q : 13	How can I execute a PHP script using command line?
Answers : 13	Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument.
Q : 14	Suppose your Zend engine supports the mode <? ?> Then how can u configure your PHP Zend engine to support <?PHP ?> mode ?
Answers : 14	In php.ini file: set short_open_tag=on to make PHP support
Q : 15	Shopping cart online validation i.e. how can we configure Paypal, etc.?
Answers : 15	Nothing more we have to do only redirect to the payPal url after submit all information needed by paypal like amount,adresss etc.
Q : 16	What is meant by nl2br()?
Answers : 16	Inserts HTML line breaks (<BR />) before all newlines in a string.
Q : 17	What is htaccess? Why do we use this and Where?
Answers : 17	.htaccess files are configuration files of Apache Server which provide a way to make configuration changes on a per-directory basis. A file, containing one or more configuration directives, is placed in a particular document directory, and the directives apply to that directory, and all subdirectories thereof.
Q : 18	How we get IP address of client, previous reference page etc ?
Answers : 18	By using $_SERVER['REMOTE_ADDR'],$_SERVER['HTTP_REFERER'] etc.
Q : 19	What are the reasons for selecting lamp (Linux, apache, MySQL, PHP) instead of combination of other software programs, servers and operating systems?
Answers : 19	All of those are open source resource. Security of Linux is very very more than windows. Apache is a better server that IIS both in functionality and security. MySQL is world most popular open source database. PHP is more faster that asp or any other scripting language.
Q : 20	How can we encrypt and decrypt a data present in a MySQL table using MySQL?
Answers : 20	AES_ENCRYPT () and AES_DECRYPT ()