request animation frame

ticker.js

var now, dt,
	rate = 0.5,
    last = performance.now();

function frame() {
	now   = performance.now();
	dt   = (now - last) / 1000;    // duration in seconds  
	if(dt >= rate){
		console.log("bing")
  		last = now;
	}
	requestAnimationFrame(frame);
}

requestAnimationFrame(frame);