Load some javascript from a CDN. Doesn't work if the response header includes Content-Security-Policy prohibiting such actions. (i.e. github)

LoadScript.js

(function (url, onLoad) {
    var script = document.createElement('script');
    script.addEventListener('load', onLoad);
    script.src = url;
    document.getElementsByTagName('head')[0].appendChild(script);
}('https://cdnjs.cloudflare.com/ajax/libs/q.js/0.9.2/q.js', function () {
    
    // Load the Q promises library dynamically and print out the object
    console.log(Q);
}))