ajax

[louenlax]

What role does Asynchronous Javascript play in the AJAX methodology? Based on the Greiner (2007) article, what role does Asynchronous Javascript play in the AJAX methodology? How does AJAX minimize the traffic between the server and client?
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[raymond]

Hi ,

Let me try to see how best to describe the "AJ" in AJAX:

When a browser makes a request to a web server the content of the page is downloaded before the web page can be rendered. When a form is submitted to the the server a couple of things take place:

1. The content of the form is sent to the server
2. The server process the data and sends back the result
3. The entire web page is reload to display the new content from the server.

In an Asynchronous JavaScript request the browser makes a separate asynchronous request to the server without having the reload the entire web page. This makes it possible to update small portions of the web page without having to download the entire page. Here's how an Ajax request is process:

1. JavaScript is used to submit an asynchronous request to the server
2. The server processes the request and returns a smalls amount of data or html to the client
3. JavaScript is then used to process the returned data and update the web page if necessary

There a re a few advantages to using Ajax:

1. Developer can control the amount of information that is submitted to the server
2. Only small amount of data needs to be rendered or processed after each request. This leads to faster page updates.
3. Request is asynchronous so client can continue working while a request is being submitted to the server.
4. Faster response time.

There are times when it is right to use AJAX and there are times when it might not be right technology for the job. AJAX works best when you're updating or processing small portions of a web page or small portions of data.