[systemiv]

function makeRequest() {
	httpRequest = new XMLHttpRequest();
	httpRequest.onreadystatechange = function () {
		getProduct(httpRequest);
	};
	url = 'test.php';
	httpRequest.open('POST', url, true);
	httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	httpRequest.send(null);
}

function getProduct(httpRequest) {
	var jsonText = httpRequest.responseText;
	jsonText = jsonText.json;
	document.write(jsonText.one);
}

Как?