website progress bar

progressbar.js

(function() {
  var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame ||
                              window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
  window.requestAnimationFrame = requestAnimationFrame;
})();

var start = null;

var d = document.getElementById("SomeElementYouWantToAnimate");
d.style.backgroundColor = 'red';
d.style.color = 'red';
d.style.height = '5px';

function step(timestamp) {
  var progress;
  if (start === null) start = timestamp;
  progress = timestamp - start;
  d.style.width = Math.min(progress/10, 100) + "%";
  if (progress < 1000) {
    window.requestAnimationFrame(step);
  } else {
    d.style.opacity = 0;
  }
}
window.requestAnimationFrame(step);

Don't forget to add this in HTML

 <div id="SomeElementYouWantToAnimate"></div>