slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
ajax PowerPoint Presentation
Download Presentation
ajax

Loading in 2 Seconds...

play fullscreen
1 / 13

ajax - PowerPoint PPT Presentation


  • 329 Views
  • Uploaded on

Its a web-technology, which speeds up web applications

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'ajax' - guest16192


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

AJAX

Bharath. P Information Science dept.

Sapthagiri college of engineering

agenda
Agenda
  • What is AJAX?
  • Overview
  • History
  • How it works?
  • Request phase implementation
  • Response phase implementation
  • Examples of Request and Response phase
  • Advantages and Disadvantages
what is ajax
What is AJAX?
  • Asynchronous Javascript and XML.
  • It is a client-side technology that combines a set of known technologies in order to create faster and more user friendly web pages.
  • It provides responsiveness approaching to that of desktop applications.
overview
Overview
  • AJAX is meant to speed web apps that have frequent user interactions.
  • Technologies used mainly are javascirpt, xml, DOM, css…
  • It shortens the required time for both document transmission and document rendering.
  • When browser requests a new part of its displayed document from the server, it doesn’t lock up waiting for response, thus its Asynchronous.
history
History
  • Use of <iframe> element which is made invisible by setting width and height to zero, although this worked, it was not elegant.
  • Microsoft introduced 2 extensions to DOM with XmlDocument and XmlHtml (XmlHttpRequest) objects.
  • It got popular from 2005/06 with google maps and gmail popularizing it.
request phase implementation
Request phase implementation
  • Object declaration of type XmlHttpRequest.
  • Registering function that implements the receive phase of the application using onreadystatechange property.
  • Call to open method to set parameters (Http method, URL of response document on the server, Asynchronous or synchronous) for HttpRequest.
  • Call to send method to send the HttpRequest to server.
response phase implementation
Response phase implementation
  • Check value of callback from server to see whether processing of request is completed.
  • Get the response using responsetext property of XmlHttprequest object.
  • Display the output in a desired way.
example of request phase
Example of Request phase
  • Varxhr= new XmlHttpRequest();

xhr.onreadystatechange= response;

xhr.open(“GET”, “reply.php?....”,true);

xhr.send(null);

example of response phase
Example of Response phase
  • Function response()

{

if(xhr.readystate == 4) {

var result=xhr.responsetext;

// any desired code

}

advantages
Advantages
  • Independent of server technology.
  • Apart from obtaining the XMLHTTP object, all processing is same for all browser types, because Javascript is used.
  • Permits the development of faster and more interactive desktop like interface to users.
disadvantages
Disadvantages
  • The back button problem. People think that when they press back button, they will return to the last change they made, but in AJAX this does not hold.
  • Requests ActiveX to be enabled in IE 5 and 6Is only available in newer versions of Opera, firefox and Safari
  • Has small implementation differences between browsers