DanielDaugherty AJAX

							      AJAX
   Daniel Daugherty
Daniel_cfug@danield.us
            What is AJAX
Asynchronous JavaScript and XML
Other terms to know
   XMLHttpRequest
   JSON
       What is AJAX used for
Data retrivial
Send data to the server for processing.
Form Validation
Anything you might load a new page for.
   It is possible to build “One Page” Ajax
    Applications.
       What is AJAX NOT
AJAX is NOT DHTML
AJAX is commonly used allong with
DHTML to provide enhanced user
interface. But they are 2 separate things.
         How to implement AJAX

Write XMLHttpRequest your self.
Use a AJAX Framework.
   Many many many many frameworks out
    there.
   DWR for JAVA
   AJAX.CFC + DWR.CFC for Coldfusion.
           DWR Setup
Download DWR –
http://getahead.ltd.uk/dwr/
Install DWR.jar in your J2EE server
classpath.
Edit web.xml to add the DWR as a servlet.
Edit DWR.XML to list objects to be made
available via AJAX.
    AJAX.CFC /DWR.CFC
Unzip AJAX.zip into a folder in your web
root.
Edit DWR.XML to list objects to be made
available via AJAX
How do I call DWR/AJAX.CFC
JS templates are needed
engine.js
util.js optional but recomeneded.
JAVA
   dwr/interface/[JavascriptName].js
ColdFusion
   ajax_js_stub.cfm?component=[JavascriptName]
   wddx.js
Demo
                  Security
Limit the type of things available via AJAX.
Java
   Supports restriction with J2EE roles
   Security Filter.
ColdFusion
   Application.cfm or Application.CFC
   cflogin roles
             Error Handling
Client Side
   DWREngine.setWarningHandler()
   DWREngine.setErrorHandler()
Server Side
   May need to adjust server side error trapping
    to be AJAX aware.
                Debugging
Server side
   LOG files are your friend.
Client Side
   Firefox Javascript Debugger
   Firebugs
   HTTP Trace utility
   Javascript alert()
   DDumper.js - Comes with AJAX.CFC