reveal.js subliminal messages

gistfile1.txt

var images = [
  '<img src="img/starbucks.png">',
  '<img src="img/google.png">'
];

var flash = function(id, image) {
  var target = document.getElementById(id);
  var goodHTML = target.innerHTML;

  target.innerHTML = image;

  setTimeout(function() {
    document.getElementById(id).innerHTML = goodHTML;
  }, 1)
};

setInterval(function() {
  flash('current', images[Math.floor(Math.random()*images.length)]);
}, 20000);