Head Rush Ajax

182

Chapter 3

Finishing up serveDrink()

Let’s spend a little time practicing with the JavaScript substring() method,

using the string you saw on the last two pages.

JavaScript

PHP script

HTML form

completing the callback function

function serveDrink() {

if (request.readyState == 4) {

if (request.status == 200) {

var response = request.responseText;

var whichCoffeemaker = response.substring(0, 1);

var name = response.substring(1, response.length);

if (whichCoffeemaker == “1”) {

var coffeemakerStatusDiv1 =

document.getElementById(“coffeemaker1-status”);

replaceText(coffeemakerStatusDiv1, “Idle”);

} else {

var coffeemakerStatusDiv2 =

document.getElementById(“coffeemaker2-status”);

replaceText(coffeemakerStatusDiv2, “Idle”);

}

alert(name + “, your coffee is ready!”);

} else

alert(“Error! Request status is “ + request.status);

}

}

These two lines

should be pretty

routine by now.

We want just the very rst position

in order to get the number of the

coffee maker that nished up.

The name

returned by the

server starts

in the second

position (“1”), and

goes to the end

of the string.

This code updates the status of

whichever coffee maker nished brewing.

This last bit just lets

the person who placed

an order know that his

coffee is now ready.

you’re on your way 4

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