window.cancelAnimationFrame()

window.cancelAnimationFrame(requestID);

var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame ||
                            window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;

var cancelAnimationFrame = window.cancelAnimationFrame || window.mozCancelAnimationFrame;

var start = Date.now();

var myReq;

function step(timestamp) {
  var progress = timestamp - start;
  d.style.left = Math.min(progress / 10, 200) + 'px';
  if (progress < 2000) {
    // it's important to update the requestId each time you're calling requestAnimationFrame
    myReq = requestAnimationFrame(step);
  }
}
myReq = requestAnimationFrame(step);
// the cancellation uses the last requestId
cancelAnimationFrame(myReq);