JavaScript Promise

promise.md

function fetchJSON(url) {
	return new Promise(function(resolve, reject) {
		var xhr = new XMLHttpRequest();
		xhr.open('GET', url);
		xhr.responseType = 'json';
		xhr.send();
		xhr.onload = function() {
			if(xhr.response) {
				resolve(xhr.response);
			}
			reject('JSON Error');
		};
		xhr.onloadend = function() {
			reject('Network Error');
		}
	});
}
function showResult(response) {
	console.log(response);
}
function handleError(response) {
	console.log(response);
}
var url = 'http://www.basecss.net/lab/all.json';
fetchJSON(url).then(showResult, handleError);