AJAX XMLHttpRequest
The keystone of AJAX is the XMLHttpRequest object.
AJAX uses the XMLHttpRequest object
To get or send information from/to a database or a file on the server with
traditional JavaScript, you will have to make an
HTML form, and a user will have to click
the "Submit" button to send/get the information, wait for the server to respond, then a new page will load with the
results. Because the server returns a new page each
time the user submits input, traditional web applications can
run slowly and tend to be less user-friendly.
With AJAX, your JavaScript communicates directly with the server, through the
JavaScript XMLHttpRequest object.
With the XMLHttpRequest object, a web page can make a request to, and get a response from a web
server - without reloading the page. The user will stay on the same page, and he
or she will
not notice that scripts request pages, or send data to a
server in the background.
The XMLHttpRequest object is supported in all major browsers (Internet Explorer,
Firefox, Chrome, Opera, and Safari).
AJAX - Browser support
All new browsers use the built-in JavaScript XMLHttpRequest object to create
an XMLHttpRequest object (IE5 and IE6 uses an ActiveXObject).
The JavaScript code for creating an XMLHttpRequest object:
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
return new XMLHttpRequest();
}
if (window.ActiveXObject)
{
// code for IE6, IE5
return new ActiveXObject("Microsoft.XMLHTTP");
} |
The next chapter shows how to use the XMLHttpRequest object to communicate with
a PHP server.
More about the XMLHttpRequest object
If you want to read more about the XMLHttpRequest, visit our
AJAX tutorial.
The Altova MissionKit, recent winner of the Jolt Product Excellence and Productivity Award for Best Development Environment,
is an integrated suite of tools ideal for:
- XML development
- Web & Web services development
- Data mapping & integration
- Rendering & publishing XML & database data
- XBRL validation, taxonomy editing, transformation & rendering
The MissionKit for XML Developers includes XMLSpy®, MapForce®, and StyleVision® plus 3 additional tools for less than the price of 2.
Try all 6 products free for 30 days!
Download a fully-functional free trial
|
|
|
|
