JSON - Introduction
JSON - Evaluates to JavaScript Objects
The JSON format is syntactically identical to the code for creating JavaScript objects.
Because of this similarity, instead of using a parser (like XML does), a JavaScript program can use standard JavaScript functions to convert JSON data into native JavaScript objects.
Try it Yourself
With our editor, you can edit JavaScript code online and click on a button to view the result:
JSON Example
<!DOCTYPE html>
<html>
<body>
<h2>JSON Object Creation in
JavaScript</h2>
<p id="demo"></p>
<script>
var text = '{"name":"John
Johnson","street":"Oslo West 16","phone":"555 1234567"}';
var obj =
JSON.parse(text);
document.getElementById("demo").innerHTML =
obj.name + "<br>" +
obj.street + "<br>" +
obj.phone;
</script>
</body>
</html>
Try it yourself »Much Like XML Because
- Both JSON and XML is "self describing" (human readable)
- Both JSON and XML is hierarchical (values within values)
- Both JSON and XML can be parsed and used by lots of programming languages
- Both JSON and XML can be fetched with an XMLHttpRequest
Much Unlike XML Because
- JSON doesn't use end tag
- JSON is shorter
- JSON is quicker to read and write
- JSON can use arrays
The biggest difference is:
XML has to be parsed with an XML parser, JSON can be parsed by a standard JavaScript function.
Why JSON?
For AJAX applications, JSON is faster and easier than XML:
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
- JSON.Parse the JSON string
