Head Rush Ajax

you’re on your way 4

161

asynchronous applications

Now wait just a second. That’s it? You

completely forgot something—what if

the rst coffee maker is already brewing

coffee? And what about the second coffee

maker? When should we use it?

Each coffee maker can only brew one cup at a time, so what if

the rst coffee maker is already brewing coffee? Somehow we

need to nd out if the rst coffee maker status is “Idle” before

we send a new request. If it’s busy, we can try the second

coffee maker. And if that one’s busy... well, then Jim’s gonna

have to wait a bit for his coffee.

How do you think we can get the status of each coffee maker?

Here’s the HTML for the rst coffee maker... what do you

think we should do?

<div id=”coffeemaker1”>

<h2>Coffee Maker #1</h2>

<p><img src=”images/CoffeeMaker1.gif”

alt=”Coffee Maker #1” /></p>

<div id=”coffeemaker1-status”>Idle</div>

</div>

Which coffee maker should we use?

Remember, the second

coffee maker HTML is

very similar to this.

How do you think we can nd out the status of the coffee

makers? And how can we update the status when one is

brewing coffee, and when the coffee maker nishes brewing?

brain

power

Keep thinking about

this, and we’ll come

back to it a little

later in the chapter.