sea-witch/demo-request-animation-frame.html

## demo-request-animation-frame.html
<html>

  <body>
    <div id="smiley" style="position: absolute;">😌</div>

    <script>
      const {requestAnimationFrame} = window

      let i = 0
      const smiley = document.querySelector('#smiley')

      function step() {
        update()
        requestAnimationFrame(step)
      }

      function update() {
        i = i < 200 ? i + 1 : 0
        smiley.style.left = Math.sin(i / 10) * 10 + 50
        smiley.style.top = i / 2
      }

      step()
    </script>
  </body>
</html>
	<html>

	<body>
	<div id="smiley" style="position: absolute;">😌</div>

	<script>
	const {requestAnimationFrame} = window

	let i = 0
	const smiley = document.querySelector('#smiley')

	function step() {
	update()
	requestAnimationFrame(step)
	}

	function update() {
	i = i < 200 ? i + 1 : 0
	smiley.style.left = Math.sin(i / 10) * 10 + 50
	smiley.style.top = i / 2
	}

	step()
	</script>
	</body>
	</html>