[Passing Ajax Data To Php With Javascript]

Hi Larry,
 
Great fan of you books! I've recently gone over Chapter 11 and I had a question regarding passing data from JSON to PHP using the code provided in the book for test.js (434-436).  I've modified the script to use JSON and that works beautifully.  I'd like to know if there is a clean JS solution to pass data to PHP without relying on jQuery.ajax({ data })?  
 
I've looked everywhere for a solution but the solution seems easily resolved with jQuery, but I'd like to avoid that if possible.
 
Here is the code I've used as dictated in the book:

 

window.onload = function() {
	'use strict';
	var ajax = getXMLHttpRequestObject();
	
	ajax.onreadystatechange = function() {
		if ( ajax.readyState == 4 ) {
			if ( (ajax.status >= 200 && ajax.status < 300) || (ajax.status == 304) ) {
				var data = JSON.parse(ajax.responseText);
				var file = '';
				file += 'Original: ' + data['org'].file + '<br>';
				file += 'Processed: ' + data['pre'].file + '<br>';
				document.getElementById('output').innerHTML = file;	
			} else {
				document.getElementById('output').innerHTML = 'Error: ' + ajax.statusText;
			}
		}
	};
	
	document.getElementById('btn').onclick = function() {
		ajax.open('POST', 'resources/test.json', true);
		ajax.setRequestHeader('Content-Type', 'application/json');
		ajax.send(null);
	};
};

 

I would like to be able to echo out the data['org'].file and data['pre'].file in PHP after the request is made.  Any guidance or suggesting would be appreciated.