JSON-JavaScript Object Notation

JSON is a syntax for passing around objects that contain name/value pairs, arrays and other objects.
It is a lightweight text-based open standard designed for human-readable data interchange.
And it is language-independent, with parsers available for virtually every programming language.The JSON format is often used for transmitting structured data over a network connection.
JSON is primarily used to transmit data between a server and web application, serving as an alternative to XML.

JSON Format

• An object is an unordered set of name/value pairs.
• An object begins with { (left brace) and ends with } (right brace).
• Each name is followed by : (colon).
• The name/value pairs are separated by , (comma).
• An array begins with [ (left bracket) and ends with ] (right bracket). Values are separated by , (comma).
  

The following example shows the JSON representation of an object that describes a employee.

The object has string fields for first name and last name, a number field for age, contains an object representing the person's address, and contains a list (an array) of phone number objects.

{"employee":{
  "firstName": "John",
  "lastName": "Smith",
  "age": 25,
  "address":
  [
  {
      "streetAddress": " Street",
      "city": "New York",
   }
  ]
     "phoneNumber":
  [
      {
        "type": "home",
        "number": "212 555-1234"
      },
      {
        "type": "fax",
        "number": "646 555-4567"
      }
  ]
}
}

References:
http://www.json.org/
http://secretgeek.net/json_3mins.asp