create worker form <script> blob url

gistfile1.js

function makeWorker(fn, args, callback) {
    var fnString = 'self.addEventListener("message", function (e) {self.postMessage((' + fn.toString() + ').apply(this, e.data))});',
        blob = new Blob([fnString], { type: 'text/javascript' }),
        url = URL.createObjectURL(blob),
        worker = new Worker(url);

    worker.postMessage(args);
    worker.addEventListener('message', function (e) {
        URL.revokeObjectURL(url);
        callback(e.data);
    });
    
    return worker;
}