animation.js

function onScroll (evt) { // Store the scroll value for laterz. 
	lastScrollY = window.scrollY; // Prevent multiple rAF callbacks. 

	if (scheduledAnimationFrame) return; 

	scheduledAnimationFrame = true; 

	requestAnimationFrame(updatePage); 
} 

window.addEventListener('scroll', onScroll, false);

Second-example.js

var globalID;

function repeatOften() {
  $("<div />").appendTo("body");
  globalID = requestAnimationFrame(repeatOften);
}

$("#stop").on("click", function() {
  cancelAnimationFrame(globalID);
});

$("#start").on("click", function() {
  globalID = requestAnimationFrame(repeatOften);
});


// requestAnimationFrame(repeatOften);