Description JSON

JSON   is a syntax for serializing objects, arrays, numbers, strings, booleans, and null.

It is based upon JavaScript syntax but is distinct from it: some JavaScript is not JSON, and some JSON is not JavaScript.

  1. Characteristic of JSON:
  • Property names must be double-quoted strings; trailing commas are forbidden.
  • Leading zeros are prohibited, a decimal point must be followed by at least one digit.
  • May be escape, certain control characters are prohibited.
  • The Unicode line separator and paragraph separator, characters are permitted.
  • Strings must be double-quoted.

2.  Methods:

2.1. JSON.parse:

  • Parse a string as JSON, optionally transform the produced value and its properties, and return the value.
  • Function:

A function that transforms the results. This function is called for each member of the object. If a member contains nested objects, the nested objects are transformed before the parent object. For each member, the following occurs:

If reviver returns a valid value, the member value is replaced with the transformed value.

If reviver returns the same value it received, the member value is not modified.

If reviver returns null or undefined, the member is deleted.

  • Return value: an object or array.

2.2. JSON.stringify:

  • Return a JSON string corresponding to the specified value, optionally including only certain properties or replacing property values in a user-defined manner.
  • Function:

Required. A JavaScript value, usually an object or array, to be converted.

Optional. A function or array that transforms the results.

If replacer is a function, JSON.stringify calls the function, passing in the key and value of each member. The return value is used instead of the original value. If the function returns undefined, the member is excluded. The key for the root object is an empty string: “”.

If replacer is an array, only members with key values in the array will be converted. The order in which the members are converted is the same as the order of the keys in the array. The replacer array is ignored when the value argument is also an array.

  • Return value: A string that contains the JSON text.

3. The JSON object is not supported in older browsers. You can work around this by     inserting the following code at the beginning of your scripts, allowing use of JSON object in implementations which do not natively support it (like Internet Explorer 6).

 

 

Introducing Json

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write.

JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. JSON is built on two structures:
A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
Exchanging Data
When exchanging data between a browser and a server, the data can only be text.
JSON is text, and we can convert any JavaScript object into JSON, and send JSON to the server.
We can also convert any JSON received from the server into JavaScript objects.
This way we can work with the data as JavaScript objects, with no complicated parsing and translations.
Sending Data
If you have data stored in a JavaScript object, you can convert the object into JSON, and send it to a server.

 

JSON: What It Is, How It Works, & How to Use It

This week I want to cover a topic that I feel has become an important part of any developer’s toolkit: the ability to load and manipulate JSON feeds from other sites via AJAX. Many sites are sharing data using JSON in addition to RSS feeds nowadays, and with good reason: JSON feeds can be loaded asynchronously much more easily than XML/RSS. This article will cover the following:

  • What is JSON?
  • Why does JSON matter?
  • How do we use JSON in a project?

We’ll also use our newfound skills with JSON at the end of this project to build a quick app that loads photos from Flickr without requiring a page refresh.

What Is JSON?

JSON is short for JavaScript Object Notation, and is a way to store information in an organized, easy-to-access manner. In a nutshell, it gives us a human-readable collection of data that we can access in a really logical manner.

Why Does JSON Matter?

With the rise of AJAX-powered sites, it’s becoming more and more important for sites to be able to load data quickly and asynchronously, or in the background without delaying page rendering. Switching up the contents of a certain element within our layouts without requiring a page refresh adds a “wow” factor to our applications, not to mention the added convenience for our users. Because of the popularity and ease of social media, many sites rely on the content provided by sites such as Twitter, Flickr, and others.

How Do We Load JSON into a Project?

One of the easiest ways to load JSON data into our web applications is to use the $.ajax() method available in the jQuery library.

This example would request the latest feed items in JSON format and output them to the browser. Obviously, we wouldn’t want to output raw JSON data to the browser, but this example shows the basics of loading JSON from an external source.