Book Image

JavaScript and JSON Essentials

By : Sai S Sriparasa
Book Image

JavaScript and JSON Essentials

By: Sai S Sriparasa

Overview of this book

The exchange of data over the Internet has been carried out since its inception. Delimiter-separated lists such as CSV and tag-separated languages such as XML are very popular, yet they are considered to be verbose by a section of developers. JSON (JavaScript Object Notation) is a lightweight text-based code to create objects to transfer data over the Internet. It is a data exchange format that is human-readable (like XML, but without the markup around your actual payload) and its syntax is a subset of the JavaScript language that was standardized in 1999. JavaScript and JSON Essentials is a step-by-step guide that will introduce you to JSON and help you understand how the lightweight JSON data format can be used in different ways either to store data locally or to transfer data over the Internet. This book will teach you how to use JSON effectively with JavaScript. This book begins with a brief refresher course on JavaScript before taking you through how JSON data can be transferred via synchronous, asynchronous, and cross-domain asynchronous HTTP calls. JSON is not just about data transfer; this book throws light on the alternate implementations of JSON as well. You will learn the data types that JavaScript uses and how those data types can be used in JSON. You will go through the concepts of how to create, update, parse, and delete a JSON object. You will also look at the different techniques of loading a JSON file onto a web page, how to use jQuery to traverse through an object, and how to perform access operations. You will also go over a few resources that will make debugging JSON quick and easy.
Table of Contents (15 chapters)

Making GET and POST AJAX calls with JSON data


It is important to understand that both synchronous and asynchronous calls are made over HTTP, so the data transfer process is the same. The popular methods to transfer data from the client machine to the server machine are GET and POST. The most common request method in HTTP is GET. When a client requests a web page, the web server uses the URL to process the HTTP request. Any other parameters that are appended to the URL serve as the data that is being sent from the client to the server. Since the parameters are part of the URL, it is important to make a clear distinction between when to and when not to use the GET request method. The GET method should be used to pass idempotent information such as a page number, a link address, or the limits and offsets that are a part of pagination. Keep in mind that there is a size constraint as to how much data can be transferred via the GET request method.

The POST request method is commonly used while...