throttle.js

// Another poor man's vanilla throttle script
window.addEventListener('scroll', throttle(callback, 1000));


// v1
function throttle(fn, wait) {
  var time = Date.now();
  
  return function() {
    if (time + wait - Date.now() < 0) {
      fn();
      time = Date.now();
    }
  };
}

// v2
function throttleTwo(callback, delay) {
  var timeout;

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

    clearTimeout(timeout);

    timeout = setTimeout(function() {
      callback.apply(context, args);
    }, delay);
  };
}