function debounce(callback, wait) {
  var timeout;

  return function() {
    var context = this;
    var args = arguments;

    var later = function() {
      timeout = null;
    }

    var callNow = !timeout;

    clearTimeout(timeout);
    timeout = setTimeout(later, wait);

    if (callNow) callback.apply(context, args);
  }
}