Blink

blink.js

// YOUR CODE GOES HERE
(function($) {
  $.fn.blink = function(speed) {
    window.setInterval(function() {
      this.css('visibility', 'hidden');
    }.bind(this), speed);

    window.setInterval(function() {
      this.css('visibility', 'visible');
    }.bind(this), speed*2);

    return this;
  };
}(jQuery));