function throttle(fn, delay, context) {
  var timer;
  var context = context || this;
  var first = true;
  return function() {
    if (first) {
      fn.apply(context, [].slice.apply(arguments));
      first = false;
    }
    if (timer) {
      return;
    }
    timer = setTimeout(function() {
      clearTimeout(timer);
      timer = null;
      fn.apply(context, [].slice.apply(arguments));
    }, delay);
  }
}

function debounce(fn, delay, context) {
  var timer;
  var context = context ||this;
  return function() {
    clearTimeout(timer);
    timer = setTimeout(fn || function() {
      fn.apply(context, [].slice(arguments));
    }, delay);
  }
}