Head Rush Ajax

you’re on your way 4

85

ajax requests

getCustomerInfo() at a glance

function getCustomerInfo() {

var phone = document.getElementById(“phone”).value;

createRequest();

var url = “lookupCustomer.php?phone=” +

escape(phone);

request.open(“GET”, url, true);

request.onreadystatechange = updatePage;

request.send(null);

}

You’ve already set up the Break Neck

form to call this function whenever the

phone number eld is changed.

Here’s the URL for the

script on the server...

...and this sends the

phone number as a

request parameter.

This sets up

the request

object to make

a GET request.

This tells the browser what

function to run when the

request’s ready state changes.

This last line sends the

request, with no additional

data other than what is

in the request URL.

This is the code to get the

phone number, using the DOM,

that you wrote in Step 1.

You wrote this

function in

Chapter 1; it

creates a new

request object.

Say What?

?

?

It’s OK if you’ve still got some questions about this code.

We’re going to look at each line in detail throughout the

chapter, so don’t feel like you have to understand it all now.

You should be pretty comfortable with making a GET request after

xing up Katie’s Boards ‘R’ Us app back in Chapter 1. Here’s

similar code for getCustomerInfo(); most of this JavaScript

should look similar to the code you wrote Chapter 1: