ChrisBuchholz/app.js

## app.js
var init = sync(function* (resume) {
    var data1, data2;

    console.log('Start by waiting for a second...');

    yield sleep(1000, resume);

    console.log('Then send a GET request to a couple of websites with XMLHttpRequest');

    data1 = yield get('https://cors-test.appspot.com/test', resume);
    data2 = yield get('https://cors-test.appspot.com/test', resume);

    console.log(data1);
    console.log(data2);
});

init();

## index.html
<!doctype html>
<meta charset=utf-8 />
<script src="lib.js"></script>
<script src="app.js"></script>

## lib.js
var sync = function (generator) {
    return function() {
        var iterator, resume;

        resume = function() {
            if (!arguments[0]) iterator.next(arguments[1]);
            else iterator.throw(arguments[0]);
        };

        iterator = generator(resume);
        iterator.next();
    };
};

var get = function(url, resume) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url, true);
    xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
            if (xhr.status === 200)
                resume(null, xhr.responseText);
            else
                resume('Failed to fetch ' + url);
        }
    };
    xhr.send(null);
};

var sleep = function(ms, resume) {
    setTimeout(resume, ms);
};
	var init = sync(function* (resume) {
	var data1, data2;

	console.log('Start by waiting for a second...');

	yield sleep(1000, resume);

	console.log('Then send a GET request to a couple of websites with XMLHttpRequest');

	data1 = yield get('https://cors-test.appspot.com/test', resume);
	data2 = yield get('https://cors-test.appspot.com/test', resume);

	console.log(data1);
	console.log(data2);
	});

	init();
	<!doctype html>
	<meta charset=utf-8 />
	<script src="lib.js"></script>
	<script src="app.js"></script>
	var sync = function (generator) {
	return function() {
	var iterator, resume;

	resume = function() {
	if (!arguments[0]) iterator.next(arguments[1]);
	else iterator.throw(arguments[0]);
	};

	iterator = generator(resume);
	iterator.next();
	};
	};

	var get = function(url, resume) {
	var xhr = new XMLHttpRequest();
	xhr.open('GET', url, true);
	xhr.onreadystatechange = function () {
	if (xhr.readyState === 4) {
	if (xhr.status === 200)
	resume(null, xhr.responseText);
	else
	resume('Failed to fetch ' + url);
	}
	};
	xhr.send(null);
	};

	var sleep = function(ms, resume) {
	setTimeout(resume, ms);
	};