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                <h1>Timed <code>requestAnimationFrame</code></h1>
<p>Click any of the buttos and watch it move down during its given duration</p>
<button data-duration="500">500ms</button>
<button data-duration="2000">2000ms</button>
<button data-duration="5000">5000ms</button>




                window.addEventListener('DOMContentLoaded', () => {

  // animateOverTime
  // - duration
  // - step callback function
  // - done callback function
  const animateOverTime = (duration = 400, stepCb = () => {}, doneCb = () => {} ) => {
    let rafId = null;
    let start = null;
    const animate = (timestamp) => {

      if (!start) start = timestamp;

      const progress = (timestamp - start)  / duration;

      if (progress > 1) {
        start = null;
      } else {
        rafId = window.requestAnimationFrame(animate);

    rafId = window.requestAnimationFrame(animate);

  // Hook click events to buttons
  document.querySelectorAll('button').forEach((button) => {

    button.addEventListener('click', (e) => {
      // Don't jump

      // Get button itself
      const $this =;
      // Prevent Double Clicks
      if ($this.classList.contains('busy')) return false;
      // Animate the element over time

        // Duration: the value of [data-duration] or 400ms by default
        $this.dataset.duration || 400,
        // Step Callback: update translateY value
        (progress) => {
          $ = `translateY(${progress * 100}%)`;
        // Done Callback: clear busy and jump back to initial position
        () => {
          $ = '';