Testing javascript injection

gistfile1.txt

var jqueryInjector = function(callback) {
    jqueryUrl = 'https://code.jquery.com/jquery-1.11.3.min.js';
    if (typeof jQuery == 'undefined') {
        var script = document.createElement('script');
        var head = document.getElementsByTagName('head')[0];
        var done = false;
        script.onload = script.onreadystatechange = (function() {
            if (!done &&
                (!this.readyState || this.readyState == 'loaded' || this.readyState == 'complete')) {
                done = true;
                script.onload = script.onreadystatechange = null;
                head.removeChild(script);
                callback();
            }
        });
        script.src = jqueryUrl;
        head.appendChild(script);
    } else {
        callback();
    }
}

gistfile2.txt

Then when you run

return this.execute(
jqueryInjector,
[],cb);

You can be sure that you have jQuery aviable.