Introduction To JSON


The following describes JSON:
  • JSON is a lightweight data-interchange format. 
  • JSON is a self-describing and easy to understand and easier to use alternative to XML.
  • JSON is language-independent.
The following are some rules of JSON Syntax:
  • JSON data consists of name/value pairs.
  • In JSON data is separated by commas. 
  • In JSON Curly Braces hold objects. 
  • In JSON Square Braces hold arrays.
JSON Data Syntax
JSON data consist of name and value pairs. It consists of a field name in double quotes (""), then a colon then a value.
JSON values can be a number, a string, a Boolean, an array, an object or null.
Syntax Of JSON Objects
JSON objects can contain multiple name/values pairs written inside Curly Braces.
Syntax Of JSON Arrays
A JSON array can contain multiple objects and are written inside Square Braces.
In this example, the object "students" is an array containing three objects. Each object is a record of a student.
Example: JSON Object Creation in JavaScript. 
  1. <!DOCTYPE html>    
  2. <html>    
  3.    <body>    
  4.       <h2>JSON Object Creation</h2>    
  5.       <p id="Result"></p>    
  7.       <script>    
  8.          var obj = JSON.parse('{"Company_Name":"C-SharpCorner","Address":"Noida","phone":"XXXXXX"}');    
  10.          document.getElementById("Result").innerHTML =    
  11.          obj.Company_Name+ "<br>" +    
  12.          obj.Address+ "<br>" +    
  14.       </script>    
  16.    </body>    
  17. </html>  
The following is the output of that:
XML has to be parsed with an XML parser, whereas JSON can be parsed by a standard JavaScript function.
The following is an XML example of student objects with 3 student records:
  1. <students>    
  2.     <student>    
  3.         <firstName>Shalin</firstName> <lastName>Dashora</lastName>    
  4.     </student>    
  5.     <student>    
  6.         <firstName>Milan</firstName> <lastName>Jain</lastName>    
  7.     </student>    
  8.     <student>    
  9.         <firstName>Priyanshi</firstName> <lastName>Dashora</lastName>    
  10.     </student>    
  11. </students>   

Similarities and Differences between JSON and XML

  • Both JSON and XML are self-describing.
  • Both JSON and XML are hierarchical.
  • Both JSON and XML can be parsed and used by many programming languages.
  • Both JSON and XML can be fetched with an XMLHttpRequest.
  • JSON doesn't use an end tag.
  • JSON is shorter.
  • JSON is quicker to read and write.
  • JSON can use arrays.
  • JSON is faster and easier, for AJAX applications.
  • XML Extracts values and stores them in variables. 
  • JSON parses JSON strings.