eloquent js chapter 13 dom ex3 cat image

by Aswin Devarajan

HTML

<p style="text-align: center">
  <img src="http://www.nesta.org.uk/sites/default/files/styles/large/public/github-cat.png" style="position: relative">
</p>

JavaScript

var cat = document.querySelector("img");
  var angle = 0, lastTime = null;
  function animate(time) {
    if (lastTime != null)
      angle += (time - lastTime) * 0.001;
    lastTime = time;
    cat.style.top = (Math.cos(angle) * 20) + "px";
    cat.style.left = (Math.sin(angle) * 200) + "px";
    requestAnimationFrame(animate);
  }
  requestAnimationFrame(animate);