XMLHttpRequest

xhr.js

request = new XMLHttpRequest();
request.open('GET', '/data/data.json', true);

request.onload = function() {
	if (this.status >= 200 && this.status < 400){
		data = JSON.parse(this.response);
		console.log(data);
	} else {
		console.log("Data error");
	}
};

request.onerror = function() {
	console.log("Connection error");
};

request.send();