Weekend MS CS Program Internet and Web Technologies COT 5930 Web Project Development - Ajax Dr. Roy Levow, Associate Chair & Professor Phone: Web:

Lesson Plan 1. Introduction to Ajax 2. Constituent Technologies A. XHTML B. CSS C. JavaScript D. DOM E. XML, XLS, XSLT F. XMLHttpRequest 3. Simple Ajax Examples

Ajax Asynchronous JavaScript And XML Provides a framework for the development of web pages that are Interactive Highly dynamic Small transfers that update current page provide faster, smoother response

Ajax Site Example Google Suggest (Beta) Google Maps Gmail Google Page Creator (Beta)

Ajax vs Classic Page Loads

Classic Synchronous Loads

Ajax Asynchronous Loads

Pros and Cons of Ajax: Pros Interactivity Achieved by direct manipulation of DOM Quick updates using incremental data loads Portability Open standards JavaScript is supported by most current browsers

Pros and Cons of Ajax: Cons Inefficiency Interpreted code Overhead of XML transfer (larger files) Portability Requires JavaScript Also requires ActiveX on IE Inconsistent rendering Issues with response to Back button Accessibility issues

Alternative Technologies Macromedia Flash Highly interactive Prepackaged “movies” Requires plugin Java Web Start Java application interacts between client and server Microsoft.NET

Ajax Component Technologies XHTML CSS JavaScript Document Object Model (DOM) XML and XSLT XMLHttpRequest

Ajax Design Principles Highly interactive Smooth responses Separation of Data Presentation Program logic

Ajax Tools A variety and growing number of tools have been developed to support Ajax technology Provide consistent development environment Hide XML and XMLHttpRequest complexity Ruby on Rails / Ajax on Rails Eclipse Ajax Tool Framework

Video Introduction Introduction to Ajax video from text what_is_ajax.mov

XHTML Provides basis for presentation of web pages Tutorial and Standard at W3Schools

Cascading Style Sheets (CSS) Provide for separation of format from content Tutorial and Standard at W3Schools

Domain Object Model (DOM) Dynamic access to elements of web page in browser Support for XHTML, XML, CSS Introduction to DOM W3 Schools XML DOM Tutorial W3 SchoolsXML DOM Tutorial Using DOM for DHTML Ryan's DHTML Tutorial, Part 4

XML Extensible Markup Language Provides basic structure for representation of data and other structured documents Tutorial and Standard at W3Schools Review of XML Namespaces

XSL Extensible Stylesheet Language More than just stylesheets For application to XML XSLT for transforming XML documents (into XHTLM) W3 Schools XSLT TutorialXSLT Tutorial XPath for selecting parts of an XML document W3 Schools XPath TutorialXPath Tutorial

References 1. Wikipedia – Ajax programming Ajax information and tutorials at Fiaminga dev 3. Ajax Blog 4. AjaxLessons.com W3Schools tutorials and standards