This site is mobile accessible. Press the "Tap Here" button to use a different font-size.

Smartphone icons created by Freepik - Flaticon

18.4 JSON Data Types

In JSON, values must be one of the following data types:
- a string
- a number
- an object (JSON object)
- an array
- a boolean
- null
JSON values cannot be one of the following data types:
- a function
- a date
- undefined

JSON Strings

Strings in JSON must be written in double quotes.

Example

{ "name":"John" }

JSON Numbers

Numbers in JSON must be an integer or a floating point.

Example

{ "age":30 }

JSON Objects

Values in JSON can be objects.

Example

{
"employee":{ "name":"John", "age":30, "city":"New York" }
}

Objects as values in JSON must follow the same rules as JSON objects.

JSON Arrays

Values in JSON can be arrays.

Example

{
"employees":[ "John", "Anna", "Peter" ]
}

JSON Booleans

Values in JSON can be true/false.

Example

{ "sale":true }

JSON null

Values in JSON can be null.

Example

{ "middlename":null }

JavaScript Fundamentals course home
Module 18. JS JSON

Navigate this module

Eventually the navigation links, above, will be replaced by these << (previous) and >> (next) buttons below.

JavaScript icons used in the buttons provided by ICONS8.COM. Smartphone icons created by Freepik - Flaticon

Example files created in this module:
JSON Syntax - Access a JavaScript object part 1 JSON Syntax - Access a JavaScript object part 2 JSON Syntax - Modify a JavaScript Object part 1 JSON Syntax - Modify a JavaScript Object part 2 JSON Parse - Parsing JSON JSON Parse - JSON From the Server JSON Parse - Array as JSON JSON Parse - Parsing Dates part 1 JSON Parse - Parsing Dates part 2 JSON Parse - Parsing Dates part 3 JSON Stringify - Stringify a JavaScript Object part 1 JSON Stringify - Stringify a JavaScript Object part 2 JSON Stringify - Storing data in local storage JSON Stringify - Stringify Dates JSON Stringify - Stringify Functions part 1 JSON Stringify - Stringify Functions part 2 JSON Objects - Creating an Object from a JSON Literal part 1 JSON Objects - Creating an Object from a JSON Literal part 2 JSON Objects - Access a JavaScript Object part 1 JSON Objects - Access a JavaScript Object part 2 JSON Objects - Looping an Object part 1 JSON Objects - Looping an Object part 2 JSON Arrays - Create JavaScript Arrays JSON Arrays - Create JavaScript Arrays part 2 JSON Arrays - Accessing Array Values JSON Arrays - Accessing Array Values in Objects JSON Arrays - Looping Through an Array JSON Server - Sending Data to a Server JSON Server - Receiving Data from a Server JSON Server - JSON From a Server JSON Server - JSON returned from a server as an array: JSON Server - Get JSON Data from a PHP Server part 1 JSON Server - Get JSON Data from a PHP Server part 2 JSON Server - Get JSON Data from a PHP Server part 3 JSON Server - Get JSON Data from a PHP Server part 4 JSON Server - Get JSON Data from a PHP Server part 5 JSON HTML - Make a table based on JSON data JSON JSONP - Request JSON using the script tag JSON JSONP - Dynamic Script Tag JSON JSONP - Callback Function