Showing posts with label XML HTTP Request. Show all posts
Showing posts with label XML HTTP Request. Show all posts

Friday, August 24, 2012

XML HTTP Request


The XMLHttpRequest Object

The XMLHttpRequest object is used to exchange data with a server behind the scenes.
The XMLHttpRequest object is a developer's dream, because you can:
  • Update a web page without reloading the page
  • Request data from a server after the page has loaded
  • Receive data from a server after the page has loaded
  • Send data to a server in the background
To learn more about the XMLHttpRequest object, study our XML DOM tutorial.

XMLHttpRequest Example

When you type a character in the input field below, an XMLHttpRequest is sent to the server - and name suggestions are returned (from a file on the server):

Type a letter in the input box:
First Name

Suggestions:


Create an XMLHttpRequest Object

All modern browsers (IE7+, Firefox, Chrome, Safari, and Opera) have a built-in XMLHttpRequest object.
Syntax for creating an XMLHttpRequest object:

xmlhttp=new XMLHttpRequest();

Old versions of Internet Explorer (IE5 and IE6) use an ActiveX Object:

xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");

In the next chapter, we will use the XMLHttpRequest object to retrieve XML information from a server.