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.
