Random Logic l Forum.NET l AJAX Behind the buzz word Forum.NET ● January 23, 2006

Random Logic l Forum.NET l What is Ajax? - Not a technology but a methodology. - A set of technologies being used together in a particular way.

Random Logic l Forum.NET l AJAX Which stands for  Asynchronous JavaScript and XML which is itself short for...  Asynchronous JavaScript  XHTML  DOM  CSS  XMLHTTPRequest

Random Logic l Forum.NET l AJAX: From another view  standards-based presentation using XHTML and CSS;  dynamic display and interaction using the Document Object Model;  data interchange and manipulation using XML and XSLT;  asynchronous data retrieval using XMLHttpRequest;  and JavaScript binding everything together.

Random Logic l Forum.NET l Is it new? Not really -Hidden frames -Good old JavaScript

Random Logic l Forum.NET l So where did it come from? Adaptive Path >> Jesse James Garrett  Q. Why did you feel the need to give this a name?  A. I needed something shorter than “Asynchronous JavaScript+CSS+DOM+XMLHttpReques t” to use when discussing this approach with clients.

Random Logic l Forum.NET l Traditional Web Application Client CSS HTML HTML GET HTML POST DatabaseServer

Random Logic l Forum.NET l Traditional Web Application

Random Logic l Forum.NET l Breaking the stop start paradigm

Random Logic l Forum.NET l AJAX the new generation

Random Logic l Forum.NET l AJAX Web Application Client HTML / XHTML XML Data CSS XSL DOM XML HTTP DatabaseServer  Controller spans the network  Standards based rich internet applications

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Random Logic l Forum.NET l Why is it popular?  Google helped popularize it in GMail  Increase Usability of Web Applications  Rich Internet Applications without Flash  Save Bandwidth  Download only data you need  Faster interfaces (sometimes)  Solves User Frustration

Random Logic l Forum.NET l Why is it bad?  Breaks back button support  URL's don't change as state changes  Cross Browser Issues can be a pain  Using Ajax for the sake of Ajax  Can't access domains other than the calling domain  May be disabled (for security reasons) or not available on some browsers  Debugging

Random Logic l Forum.NET l Browser support  Browsers that support Ajax  Apple Safari 1.2 and above  Konqueror  Microsoft Internet Explorer 4.0 and above  Mozilla Firefox 1.0 and above  Netscape 7.1 and above  Opera 7.6 and above

Random Logic l Forum.NET l AJAX in the real world

Random Logic l Forum.NET l Examples of AJAX  GMail  Google Maps Google Maps  Google Suggest Google Suggest  NetVibes NetVibes

Random Logic l Forum.NET l XMLHttpRequest  A JavaScript Class that lets you make asynchronous HTTP requests from JavaScript  Make an HTTP request from a JavaScript event  A call back JavaScript function is invoked at each state of the HTTP request and response  Native XMLHttpRequest support should be in IE7

Random Logic l Forum.NET l XMLHttpRequest Properties  onreadystatechange - call back function for state changes  readyState - the current state of the HTTP call  responseText - the text result of the request  responseXML - DOM xml object from the request  status - HTTP status code of the response  statusText - HTTP status text

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Random Logic l Forum.NET l A simple example XML file

Random Logic l Forum.NET l Ajax.NET – How it works  Add reference ajax.dll to your project  Modify your web.config to configure IHttpHandler for Ajax.NET requests  Write your methods in C#/VB.NET and add the attribute [AjaxMethod]  Call Class1.Method1(param1, param2, callback, context); from client-side JavaScript

Random Logic l Forum.NET l Demo AJAX.NET

Random Logic l Forum.NET l Ajax.NET – Key Benefits  Methods only get attribute, no need to implement interface or inherit from class [AjaxMethod] public int GetAge(string username){…}  Source-code doesn‘t change if you want to use the method in server-side code DemoMethods dm = new DemoMethods(); int age = dm.GetAge(“michael“);

Random Logic l Forum.NET l Ajax.NET – Key Benefits  Client-side JavaScript will get “real“ objects from Ajax.NET calls using JSON function test_callback(res) { alert(res.value.FirstName + ‘ ‘ + res.value.FamilyName); }  DataSet, DataTable, DataRow, ArrayList, Array, DateTime, TimeSpan, …  Create your own IAjaxObjectConverters

Random Logic l Forum.NET l Ajax.NET – Key Benefits  Cache requests (CacheDurationTimeSpan)  Access SessionState objects using HttpContext.Current.Session[…]  Unicode support without use of XML parser  Use Ajax.NET to retreive “events“ instead of polling

Random Logic l Forum.NET l Conclusion  AJAX enable more interactive, more responsive, and smarter Web applications.  AJAX is not tied to a particular programming language.  Remember AJAX has its cons use it wisely.

Random Logic l Forum.NET l Questions?

Random Logic l Forum.NET l Thank You