text: window.onload = function () {
  
      var btn_play = document.getElementById("btn-play");
      var btn_pause = document.getElementById("btn-pause");
      var video = document.getElementById("video");
  
      btn_play.addEventListener('click', function () {
          video.play();
      });
  
      btn_pause.addEventListener('click', function () {
          video.pause();
      });
  
  }