Cross Browser XHR

xhr.js

// XHR
var ajax = function (method, url, data, callback) {
	var xhr = /*@cc_on!@*/true ? new XMLHttpRequest() : new XDomainRequest();
	xhr.timeout = 3000;
	xhr.ontimeout = function () {
		alert("timeout");
	};
	xhr.onerror = function () {
		alert("error");
	};
	xhr.onload = function () {
		callback(xhr.responseText);
	};
	xhr.open(method, url, false);
	if (method === "POST")
		xhr.setRequestHeader("Content-Type", "application\/x-www-form-urlencoded; charset=UTF-8");
	xhr.send(data);
};

// Usage
ajax(method, url, data, function (res) {
	console.log(res);
});

https://developer.mozilla.org/ja/XMLHttpRequest