Ajax [Asunchronous HTTP request ] - A Deep Introduction About Ajax Technology - Lets Take a Glance About Ajax ,Where it's use | Whats the purpose of Ajax in Web Application Developement . Bacis of Ajax Technology + Coding Tips ..

1. you do something without reloading

2.  It has a collection of
hard disk for storing
web pages
 Each hard disk have
1TB storage capacity
 Its connected to
network via the
computer

3. Server Side:
 information is sent to a server to be processed
 With server-side scripting, completing an activity involves
sending information to another computer (server) across
the internet. The server then runs a program that process
the information and returns the results, typically a
webpage.
 Server-side scripting languages include ASP and
PHP,PYTHON, coldfusion
Client side:
 Client-side scripting generally refers to the class of
computer programs on the web that are executed client-
side, by the user's web browser, instead of server-side (on
the web server).
 Client side scripting languages include
html,css,javascript,ajax,jquery

5.  Web server html .xml .xhtml, files
are accessed another computer via
the http request and response
protocol.
HTTP request? (its load all
page)
 Whenever your web browser fetches a
file (a page, a picture, etc) from a web
server, it does so using HTTP - that's
"Hypertext Transfer Protocol". HTTP is
a request/response protocol, which
means your computer sends a request
for some file (e.g. "Get me the file
'home.html'"), and the web server sends
back a response ("Here's the file",
followed by the file itself).
xml http request
 its load particlular pages without
reloading web page

6.  AJAX = Asynchronous JavaScript and XML.
 AJAX is the art of with exchanging data a server, and updating
parts of a web page - without reloading the whole page.
AJAX technology
 HTML (or XHTML) and CSS for presentation
 The Document Object Model (DOM) for dynamic display of and
interaction with data
 XML for the interchange of data, and XSLT for its manipulation
 The XMLHttpRequest object for asynchronous communication
 JavaScript to bring these technologies together

8. Ajax work flow
 First of all need to trigger a EVENT like
onclick,double cllick,mouse over like that,,
 Send xmlhttprequest to server and request
will be processing
 Response will be store in html file id with out
reloading using DOM object

9. Send a Request To a Server
 To send a request to a server, we use the open() and send()
methods of the XMLHttpRequest object:
xmlhttp.open("GET","ajax_info.txt",true);
xmlhttp.send();
Description
xmlhttp.open(method,url,async);
Specifies the type of request, the URL, and if the request should be
handled asynchronously or not.
method: the type of request: GET or POST
url: the location of the file on the server
async: true (asynchronous) or false (synchronous)
send(string)
Sends the request off to the server.

10. Server Response
 To get the response from a server, use the responseText or responseXML
property of the XMLHttpRequest object.sever response data format has
xml type
Server response status
 404-page not found
 403-forbidden
property desc
responseText get the response data as a
string
responseXml get the response data as a
xml docs
code desc
1xx Server connection
established
2xx Req result
3xx Process request
4xx Client error
5xx Server error

11. DOM Object for display result
 It s mainly used javascript appalication.its change the content
dynamically
 Dom object is used to store the response of the server in the
inner HTML
document.getElementById("myDiv").innerHTML=xmlhttp.re
sponseText;

12.  Better interactivity
This is pretty much the most striking benefit behind why several developers and
webmasters are switching to AJAX for their websites. AJAX allows easier and
quicker interaction between user and website as pages are not reloaded for
content to be displayed.
 Easier navigation
AJAX applications on websites can be built to allow easier navigation to users in
comparison to using the traditional back and forward button on a browser.
 Compact
With AJAX, several multi purpose applications and features can be handled using a
single web page, avoiding the need for clutter with several web pages. For our use
of AJAX on goedkope-zomervakantie.com, it took just a few lines of code!
 Backed by reputed brands
Another assuring reason to use AJAX on your websites is the fact that several
complex web applications are handled using AJAX, Google Maps is the most
impressive and obvious example, other powerful, popular scripts such as the
vBulletin forum software has also incorporated AJAX into their latest version.

13.  The back and refresh button are rendered useless
With AJAX, as
all functions are loaded on a dynamic page without the page being
reloaded or more importantly a URL being changed (except for a hash
symbol maybe), clicking the back or refresh button would take you to an
entirely different web page or to the beginning of what your dynamic
web page was processing. This is the main drawback behind AJAX but
fortunately with good programming skills this issue can be fixed.
 It is built on javascript
While javascript is secure and has been heavily
used by websites for a long period of time, a percentage of website
surfers prefer to turn javascript functionality off on their browser
rendering the AJAX application useless, a work around to this con is
present as well, where the developer will need to code a parallel non-
javascript version of the dynamic web page to cater to these users.

16. Tips for making dynamic application
 Dont need for typing code..simply search the
plugin for ajax in google
 Download it
 Link the jquery file
 Trigger the jquery file then use it
Simply done..no coding . ..
No tension........