JSON data and Its usage.

Usage of JSON

Json means java script object notation.
Json is used for transfering the data from cleint side to server or vice versa.
Json formate is text only so it can easily send to and from server.

In Json data is key value pair, with data separated by comma and 
curly braces hold object data and square bracket hold array data.

Key must be string and written in double quotes.
Value must be one of the following 
* a string
* a number
* an object (JSON object)
* an array
* a boolean
* null

date, function, undefined can't be json value.

JSON.parse()
=============
This function used to convert the json string to java script object.

JSON.stringify()
=================
This function is used to create a json string from java script objects. This function convert dates to string
any function exist, this function will remove it.



Accessing a Object value using Loop
====================================
myObj = { "name":"John", "age":30, "car":null };
for (x in myObj) {
  document.getElementById("demo").innerHTML += myObj[x];
}


In PHP
#######

json_encode
===========
Convert the PHP object to json string

json_decode
============
Convert the json string to object.

// https://stackoverflow.com/questions/383692/what-is-json-and-why-would-i-use-it