【jQuery】slickで次のスライドに切り替わるまでのプログレスバーを表示する方法のデモページ

.wrap {
  position: relative;
  width: 600px;
  margin: 70px auto 0;
}
.progress {
  position: absolute;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 10px;
  background: #eee;
}

.bar {
  display: block;
  width: 0%;
  height: 10px;
  background: #cecece;
}

@media screen and (max-width:640px){
  .wrap {
    width: 100%;
  }
}

$(function(){
  var run;
  var progress = $('.bar');
  var slick = $('.slider');
    slick.slick({
    pauseOnFocus: false,
    pauseOnHover: false,
    draggable: false,
    fade: true
  });
  function start() {
    reset();
    percentTime = 0;
    run = setInterval(interval, 10);
  }
  function interval() {
      percentTime += 0.4;

      progress.css({
        width: percentTime+"%"
      });
      if(percentTime >= 100) {
        slick.slick('slickNext');
        start();
      }
  }
  function reset() {
    progress.css({
     width: 0+'%'
    });
    clearTimeout(run);
  }
  start();
});