Head Rush Ajax

204

Chapter 4

Meet the DOM

Although you may not have realized it, you’ve been using the DOM

since way back in Chapter 1. Remember this code from Katie’s

Boards ‘R’ Us report?

(again)

function updatePage() {

var newTotal = request.responseText;

var boardsSoldEl = document.getElementById(“boards-sold”);

var cashEl = document.getElementById(“cash”);

...

}

function getCustomerInfo() {

var phone =

document.getElementById(“phone”).value;

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

escape(phone);

request.open(“GET”, url, true);

request.onreadystatechange = updatePage;

request.send(null);

}

And here’s some similar code from the Break Neck pizza app:

The document object gives

JavaScript access to the DOM tree

that the web browser creates.

Here’s that

document

object again.

The “document”

object gives

your JavaScript

access to the

web browser’s

DOM tree.

Don’t miss this... it’s

probably the most important

thing in the whole chapter!

a dom retrospective

We’ve left out the rest of the

code from this function.