use SinonJS XHR to spy on outgoing AJAX requests - useful for debugging

gistfile1.txt

// SinonJS's XHR support is great for unit testing code that makes
// AJAX requests.  But you can also use it to measure AJAX requests
// made from production code if you insert the below code snippet.

// full docs here: http://sinonjs.org/docs/#server

sinon.useFakeXMLHttpRequest();

sinon.FakeXMLHttpRequest.useFilters = true;
sinon.FakeXMLHttpRequest.addFilter(function (method, url, async, username, password) {

    if (!async) {
        alert("synchronous request detected to " + url );
    }
    console.dir({
        method: method,
        url: url,
        async: async,
        username: username,
        password: password
    });

    return true;
});