Head Rush Ajax

108

Chapter 2

You’ve seen what the Break Neck server is doing, and you’re

written a lot of new JavaScript, but what’s the browser doing as

all these ready states are changing?

Let’s take a look and nd out:

What is the browser doing?

Web Browser

Internet Explorer

Firefox

Opera

Safari

Mozilla

1

2

3

4

These are the request’s ready states.

<?php

require(‘lib.php’);

function go() {

$myVar = ...

return ...

}

?>

1

2

<script>

var request...

function foo()

{

...

}

</script>

PHP script

JavaScript

updatePage()

3

4

Request

Object

5

6

1. The browser runs

getCustomerInfo(), and a request is

made to the Break Neck web server.

2. As the request is being worked

on, the ready state of the request

is changed to reect what stage of

processing the request is in.

3. Each time the ready

state of the request

changes, the browser

runs your callback

function, updatePage().

4. updatePage() checks

the request object’s

ready state, and only

keeps running if the

request is nished.

6. If the request is nished,

updatePage() can get the server’s

response from the request object.

5. When the browser gets a

completed response from the

server, it stores the server’s

response in the request object.

Man, Break Neck pizza rocks. There’s

nothing like a breakfast of cold pizza, a

whipped latte from Starbuzz, and the

Webville Times to read.

<script>

var request...

function foo()

{

...

}

</script>

JavaScript

<script>

var request...

function foo()

{

...

}

</script>

Customer’s ...