helpers.js

  window.asyncSeries = function(series, callback, forwardExceptions) {
    series = series.slice();
    var next = function(err) {
      if (err) {
        if (callback) {
          callback(err);
        }
      } else {
        var f = series.shift();
        if (f) {
          if (!forwardExceptions) {
            f(next);
          } else {
            try {
              f(next);
            } catch(e) {
              if (callback) {
                callback(e);
              }
            }
          }
        } else {
          if (callback) {
            callback();
          }
        }
      }
    };
    next();
  };

  window.waitFor = function(fn, next, intervalOrMutationEl, timeout, timeoutTime) {
    timeoutTime = timeoutTime || Date.now() + (timeout || 1000);
    intervalOrMutationEl = intervalOrMutationEl || 32;
    try {
      fn(); 
    } catch (e) { 
      if (Date.now() > timeoutTime) {
        throw e;
      } else {
        if (isNaN(intervalOrMutationEl)) {
          intervalOrMutationEl.onMutation(intervalOrMutationEl, function() {
            waitFor(fn, next, intervalOrMutationEl, timeout, timeoutTime);
          });
        } else {
          setTimeout(function() {
            waitFor(fn, next, intervalOrMutationEl, timeout, timeoutTime);
          }, intervalOrMutationEl);
        }
        return;
      }
    }
    next();
  };