xhr.js

var ajaxPost;

(function() {
	ajaxPost = function (endPoint, obj, failCallback) {
		var xhr = new XMLHttpRequest();

		xhr.open('POST', endPoint, true);

		xhr.onload = function() {
		    if (xhr.status != 200 && xhr.status != 4) {
		        failCallback();
		    }
		};

		xhr.onerror = function() {
			failCallback();
		};

		xhr.send(JSON.stringify(obj));
	}
}());