goog.net.BulkLoader

gistfile1.js

var bulkLoader = new goog.net.BulkLoader(urls);
goog.events.listen(bulkLoader,
    [goog.net.EventType.SUCCESS, goog.net.EventType.ERROR],
    function(e) {
      if (e.type == goog.net.EventType.SUCCESS) {
        // We use unsafeParse here because we trust the source of the data.
        var loader = /** @type {goog.net.BulkLoader} */ (e.target);
        var json = goog.array.map(loader.getResponseTexts(),
                                  goog.json.unsafeParse),
        showEventsOnCalendar(json);
      } else {
        // Here, e.type is goog.net.EventType.ERROR
        alert('Oh no - I should add some error handling here!');
      }
      bulkLoader.dispose();
    });
bulkLoader.load()