JSON is a lightweight data-interchange format that is language independent and easy for humans to read and write. It uses JavaScript syntax to transmit data objects consisting of attribute-value pairs and arrays, and can be parsed by JavaScript. Unlike XML, JSON has no end tags or reserved words. JSON is commonly used to transmit data between a server and web page by parsing a JSON string into a JavaScript object using the built-in JSON.parse() method.

1. Introduction to JSON

2. What is JSON
 JSON stands for JavaScript Object
Notation
 JSON is lightweight text-data
interchange format
 JSON is language independent *
 JSON is "self-describing" and easy to
understand

3. Example JSON
{
"id":1,
"name":”Anoop",
"billingAddress":[{"city":”Bangalore"}]
}

4. JSON is LIKE XML
 JSON is plain text
 JSON is "self-describing" (human
readable)
 JSON is hierarchical (values within
values)
 JSON can be parsed by JavaScript

5. JSON is UNLIKE XML
 No end tag
 Shorter
 Quicker to read and write
 Can be parsed using built-in
JavaScript parse()
 Uses arrays
 No reserved words

6. Data on a web page
 Using XML
 Fetch an XML document
 Use the XML DOM to loop through the document
 Extract values and store in variables
 Using JSON
 Fetch a JSON string
 parse() the JSON string to get javascript objects

7. JSON Syntax
 Data is in name/value pairs
 Data is separated by commas
 Curly braces hold objects
 Square brackets hold arrays
{
"id":1,
"name":”Anoop",
"billingAddress":[{"city":”Bangalore"}]
}

8. JSON object
 JSON objects are written inside curly
brackets,
 Objects can contain multiple name/values
pairs separated by comma:
{ "firstName":"John" , "lastName":"Doe" }
 Names in objects are supposed to be
unique. If they are not unique, the last
one is returned during access

9. JSON value

10. JSON Array
 JSON arrays are written inside square brackets.
 An array can contain multiple objects:
{
"employees": [
{ "firstName":”Sanjay" , "lastName":”Adiwal" },
{ "firstName":”Shubham" , "lastName":”Parikh" },
{ "firstName":”Anoop" , "lastName":”Pandey" }
]
}

11. JSON and Javascript
var employees = ‘[
{ "firstName":”Sanjay" , "lastName":”Adiwal" },
{ "firstName":”Shubham" , "lastName":”Parikh" },
{ "firstName":”Anoop" , "lastName":”Pandey" }
]’;
obj = JSON.parse(employees)
obj[0].lastName //Adiwal
obj[0].firstName // “Sanjay";

12. JSON and other languages
» APIs are available for all
contemporary web programming
languages
» All browsers today are JSON-aware
» For server-side, specific APIs are in
Java, .Net, PHP, etc.