AJAX

1
AJAX

• Daniel Daugherty
• Daniel_cfug_at_danield.us

2
What is AJAX

• Asynchronous JavaScript and XML
• Other terms to know
• XMLHttpRequest
• JSON

3
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.

4
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.

5
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.

6
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.

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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

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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?componentJavascriptName
• wddx.js

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Demo

10
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

11
Error Handling

• Client Side
• DWREngine.setWarningHandler()
• DWREngine.setErrorHandler()
• Server Side
• May need to adjust server side error trapping to
  be AJAX aware.

12
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