Head Rush Ajax

you’re on your way 4

111

ajax requests

With the address from the server, all that’s left is to update the web

form. Since the address is stored in a form eld, you can use the

DOM again, similar to how you got the value of the phone number

eld in getCustomerInfo() way back on page 82.

function updatePage() {

if (request.readyState == 4) {

/* Get the response from the server */

var customerAddress = request.responseText;

/* Update the HTML web form */

document.getElementById(“address”).value =

customerAddress;

}

}

Since address is a form eld,

you can access the text in it

using the “value” property.

Here’s where

those id

attributes come

in handy again.

Q:

Why don’t we have to use that JavaScript utility file

from Chapter 1 to update the address field?

a: In Chapter 1, we were updating the text in a <span>

element. Since <span> isn’t an HTML element that you usually

type in, it doesn’t have a value property; the same is true for

most other HTML elements, like <p>, <em>, and <div>.

For form fields, though, you usually do need to enter a value.

To make that easier, you can just use the value property on a

form field element, and get and set its text value directly.

Q:

Couldn’t we just use a <div> for the customer’s

address? Why are we using a field, anyway?

a: Even though the Break Neck server looks up the

customer’s address, there are times when a customer might

want their pizza deliv ...