Head Rush Ajax

you’re on your way 4

3

next generation applications

Welcome to the new millenium!

Anybody can program using the same old request/response

model. But if you want faster apps that feel like you’re

working on a desktop, you need something new—you need

Ajax, a completely different approach to web programming:

For the web server, nothing has

changed; it still responds to each

request, just as it did before.

JavaScript

Request

This JavaScript code makes a

request to the server.

Web Server

Response

The JavaScript

dynamically

updates the web

page, without

redrawing

everything. Sweet!

Web Server

No more waiting around...

...when you’re using Ajax apps

The web page sends its requests

using a JavaScript function, which

handles talking to the server.

The server’s response has only the

data the page needs... without any

markup or presentation.

<script>

var request...

function foo()

{

...

}

</script>

<script>

var request...

function foo()

{

...

}

</script>

Update

JavaScript

Most of the page doesn’t change...

only the parts of the page that

need to change are updated.

4

Chapter 1

If you haven’t guessed by now, we’re talking

about how you can use Ajax to build killer

web apps. So far, you’ve seen how Ajax

applications can talk to a web server without

the browser reloading and redrawing the

entire page all the time. But ther