AJAX Asynchronous JavaScript and XML

1
AJAX(Asynchronous JavaScript and XML)

• Amit Jain
• CS 590 Winter 2008

2
AJAX Introduction

• (Asynchronous JavaScript and XML)
• Basic Principle
• Lets you manipulate the contents of a Web page
  without having to reload the page.
• How?
• By manipulating the web browser's DOM

3
DOM - Document Object Model

• Model for representing an HTML document
• Manipulation to the HTML DOM objects causes
  immediate changes

4
Example for DOM

• ltdiv id"sample"gt
• This is a ltbgtsample of HTMLlt/bgt ltbrgt to
  demonstrate the DOM
• lt/divgt

5
How to Access DOM

• From Previous Example
• // to get a reference to the DIV element
• var elmdocument.getElementById("sample")
• //following will alert 3 - TEXT NODE
• alert(elm.childNodes0.nodeType)
• // following will //will alert "this is a"
• alert(elm.childNodes0.nodeValue)

6
How JavaScript Manipulates DOM

• Hello World Example