JS Blink

Element.prototype.blink = function(i) {
  var self = this;
  this.lastDisplay = this.style.display;
  this.change = true;
  this.blinkInterval = setInterval(function() {
    if (self.change) self.style.display = 'none';
    else self.style.display = self.lastDisplay;
    self.change = !self.change;
  }, i);
}

Element.prototype.stopBlink = function() {
    if(this.blinkInterval) clearInterval(this.blinkInterval);
}

document.getElementById('b').blink(60);
document.getElementById('b').stopBlink();

// Fiddle: https://jsfiddle.net/5d2s5La8/