Head Rush Ajax

196

Chapter 3

That’s all ne, but I want to see what

happens in this application when it’s

not

asynchronous. I want to compare the

synchronous and asynchronous versions,

and see if the asynchronous version is

really that much better.

Skeptical?

So, you want to see for yourself how different the Coffee Maker

program is as a synchronous application? That’s easy to do. All you have

to do is change the third argument of the call to request.open() in

the sendRequest() function: switch it from true to false:

function sendRequest(request, url) {

request.onreadystatechange = serveDrink;

request.open(“GET”, url, false);

request.send(null);

}

Change the argument from true to false to tell

your application to send the request to the coffee

makers on the server synchronously.

Then give it a try. What happens?

synchrony versus asynchrony