difference between json and ajax? when should what be used?

Question

Hello I am completely confused between json and ajax. When would what be used. I work with PHP on the server side. I regularly use ajax to receive data asynchronously, without invoking a page load. I use php's json functions to pass data to javascript. But I just started learning jQuery, and I am completely confused when to use function ajax and when to use json. Can somebody help me out with this, thanks.

Answer 1

JSON (JavaScript Object Notation) and AJAX (Asynchronous JavaScript and XML) are two completely different concepts, one is used as a storage medium for data (JSON) while the other is used to retrieve data from a HTTP or FTP web server (AJAX) which is not dependent on the format of the data to be transferred, it can be text, binary, XML or JSON, which is pretty much everything.

You can use AJAX with JSON, by retrieving some data in the JSON format from the web server, using AJAX, then using JavaScript to parse the JSON data into a form accessible by the scripting engine.

Answer 2

I assume you are referring to the jQuery .getJSON() method.

This method is simply a shorthand way of using the jQuery .ajax() method with JSON data. .getJSON() is equivalent to:

$.ajax({
  url: url,
  dataType: 'json',
  data: data,
  success: callback
});

So, you can make use of .getJSON() if you will be retrieving JSON data from the server. The data will automatically be parsed with the jQuery.parseJSON() method.

---

In more general terms AJAX is a way to asynchronously retrieve information from a server. JSON is a way to format data.... but I assume you knew this already, and you were asking specifically about the two jQuery methods I mentioned.