Most likely, you would end up with a nightmarish tangle of UI callbacks entwined with business logic, destined to be discarded by the poor soul who inherits your code.Thankfully, there are a growing number of Java Script libraries that can help improve the structure and maintainability of your code, making it easier to build ambitious interfaces without a great deal of effort.has quickly become one of the most popular open-source solutions to these issues and in this book we will take you through an in-depth walkthrough of it.

With the server no longer being the only place that knows about our item count, it was a hint that there was a natural tension and pull of this evolution.

The rise of arbitrary code on the client-side which can talk to the server however it sees fit has meant an increase in client-side complexity.

Good architecture on the client has gone from an afterthought to essential - you can’t just hack together some j Query code and expect it to scale as your application grows.

Now this relationship has been inverted - client applications pull raw data from the server and render it into the browser when and where it is needed.

Think of the Ajax shopping cart which doesn’t require a refresh on the page when adding an item to your basket.

Initially, j Query became the go-to library for this paradigm.

Its nature was to make Ajax requests then update text on the page and so on.

Not so long ago, “data-rich web application” was an oxymoron.

Today, these applications are everywhere and you need to know how to build them.

Traditionally, web applications left the heavy-lifting of data to servers that pushed HTML to the browser in complete page loads.

The use of client-side Java Script was limited to improving the user experience.