Here is the documentation for Request.JSON.js.
Request.JSON is a wrapper class for XHR to handle automated sending and receiving of Javascript Objects in Json Format.
Basic Syntax:
var myJsonRequest = new Request.JSON(url, options)
I can't really demonstrate what this does in this tutorial, but here's an example of what you might do with it:
var jSonRequest = new Request.JSON({url: 'http://site.com/tellMeAge.php', onComplete: function(person){ alert(person.age); //is 25 years alert(person.height); //is 170 cm alert(person.weight); //is 120 kg }}).send({'name': 'John', 'lastName': 'Doe'});
In the example above, we send "John Doe" to our tellMeAge.php which presumably looks up some information about that person and returns it in a Json format that looks something like:
{ "age": "25 years", "height": "170 cm", "weight": "120 kg", "name": "John", "lastName": "Doe" }
Note that the Request.JSON class's .send method that takes a JavaScript object.