var spawn = function() {
  
  var bubble = document.createElement('div');
  bubble.style.left = (5 + (Math.random()*95)) + '%';
  bubble.style.top = '100%';
  bubble.style.webkitTransitionDuration = (25 + (Math.random() * 10)) + 's';
  document.body.appendChild(bubble);
  
  var scale = .85 + (Math.random() * .3);
  var value =  'scale(' + scale + ') translateY(' + 100 + 'px)'
  
  bubble.style.webkitTransform = value;
  bubble.style.mozTransform = value;
  bubble.style.msTransform = value;
  bubble.style.transform = value;
  bubble.offsetWidth;
  
  var value = 'scale(' + scale + ') translateY(-' + (document.documentElement.clientHeight + 200) + 'px)';
  bubble.style.webkitTransform = value;
  bubble.style.mozTransform = value;
  bubble.style.msTransform = value;
  bubble.style.transform = value;
  
  setTimeout(spawn,2000 + (Math.random() * 1000));
  
}

spawn();