A synchronous version of setInterval (functional form). Waits for the interval function to finish before starting the timeout to the next call.

setIntervalSynchronous.js

var setIntervalSynchronous = function (func, delay) {
  var intervalFunction, timeoutId, clear;
  // Call to clear the interval.
  clear = function () {
    clearTimeout(timeoutId);
  };
  intervalFunction = function () {
    func();
    timeoutId = setTimeout(intervalFunction, delay);
  }
  // Delay start.
  timeoutId = setTimeout(intervalFunction, delay);
  // You should capture the returned function for clearing.
  return clear;
};