Chapter 5. Asynchronous Applications: It’s like renewing your driver’s license

Are you tired of waiting around? Do you hate long delays? You can do something about it with asynchrony!

You’ve already built a couple of pages that made asynchronous requests to the server to avoid making the user sit around waiting for a page refresh. In this chapter, we’ll dive even deeper into the details of building asynchronous applications. You’ll find out what asynchronous really means, learn how to use multiple asynchronous requests, and even build a monitor function to keep all that asynchrony from confusing you and your users.

What does asynchronous really mean?

An asynchronous request means that you don’t have to wait around while a web server is responding to that 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 finished with your request. Let’s take a view of this from 10,000 feet by first looking at what a synchronous request is, and then comparing it to an asynchronous request: