Head Rush Ajax

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Chapter 3

What does asynchronous really mean?

Asynchronous means that you don’t have to wait around while a web server is responding to

your request. That means you’re not stuck: you can go on doing what you want, and have the

server let you know when it’s nished with your request. Let’s take a view of this from 10,000

feet by rst looking at what a synchronous request is, and compare it to an asynchronous request.

I am

so

craving a Head First cola...

Hey Rufus, will you go GET me a

Head First cola from the store?

Must get cola,

must get cola...

This is your request: you’re

asking your trusty dog

Rufus to go GET you a cola.

A synchronous request for cola

An asynchronous request for cola

You send your request...

Now, compare that to this asynchronous request...

Hey Rufus, will you get me another cola?

Once again, your trusty dog

Rufus goes off with your

request to get your cola.

This time, though, Rufus is

an ASYNCHRONOUS dog....

Like before, you make a

request to Rufus to go

GET you a cola. Except

this time, you tell him he’s

an asynchronous dog.

I’m gonna have to

ask for a pay raise.

More kibble.

what does asynchronous mean?

you’re on your way 4

141

asynchronous applications

Ow, my

back!

Good boy, Rufus! But I gotta make

you an

asynchronous

dog... my back

can’t take this anymore.

...but because ...