Do something each second using requestAnimationFrame instead of setTimeout or setInterval.

DoEachSecond

var time = new Date().getTime();
var interval = 1000;
(function update() { 
  requestAnimationFrame(update);
  var now = new Date().getTime(), 
    delta = now - (time || now); 
      
  if(delta>=interval) {
    // Update a "time ago"|"time left" or do something...
    console.log((new Date(now)).getSeconds()); 
    time = now;
  }
  
})()