Head Rush Ajax

198

Chapter 3

all is right with the world

Change that baby back to asynchronous!

Don’t forget to change sendRequest(), in coffee.js, back to the

asynchronous version... nobody wants to wait around on their caffeine x.

Two coffee makers, asynchrony, and

one jittery, wired, happy office.

you’re on your way 4

199

asynchronous applications

60 Second Review

™ Synchronous requests wait for a response

from the server before anything else is

allowed to happen.

™ Asynchronous requests don’t wait for a

response, so users can keep pounding

away at an asynchronous application while a

request is being handled.

™ A lot of Ajax applications are asynchronous,

but when a web server returns a response

quickly, it really doesn’t matter whether the

app is asynchronous or not.

™ Asynchronous applications work best when

the server takes a while to send a response

back, or when users need to do several

things at one time on a web page or form.

™ When you call a request object’s open()

method, the third parameter tells the request

whether or not it’s asynchronous. A value of

“true” means asynchronous; “false” means

synchronous.

™ The DOM allows you to change a web page

without reloading the page.

™ The innerHTML property is deprecated, and

isn’t as safe or stable an approach as using

the DOM to change a web page ...