JSON file

JSON name/value pairs
JSON data is written in the format: name/value pairs.
A name/value pair consists of the field name (in double quotes), followed by a colon, and then the value.
For example :

"firstName" : "John"

JSON objects
JSON objects are written in curly braces, and objects can contain multiple name/value pairs. E.g:

{"firstName" : "John","lastName":"Doe"}

JSON arrays are written in square brackets, and arrays can contain multiple objects:

{
"employees":[{"firstName" : "John","lastName":"Doe"},{"firstName" : "Anna","lastName":"Smith"}]
}

JSON uses Javascript syntax, so no additional software is required to process JSON in Javascript. An array of objects can be created and assigned by Javascript:

var employees = [{"firstName" : "John","lastName":"Doe"},{"firstName" : "Anna","lastName":"Smith"}
]

The first item in an array of Javascript objects can be accessed:

employees[0].lastName

What is returned is:

Doe

Convert JSON string to Javascript object
Create a Javascript string, the string is data in JSON format,

var text = '{
"employees":['+'{"firstName" : "John","lastName":"Doe"},'+'{"firstName" : "Anna","lastName":"Smith"}]
}'

Strings can be converted to Javascript objects using the Javascript built-in function JSON.parse():

var obj = JSON.parse(text);

The return value is

{
"employees":[{"firstName" : "John","lastName":"Doe"},{"firstName" : "Anna","lastName":"Smith"}]
}

JSON.stringfy() is used to convert Javascript values ​​to JSON strings