function Blinker(el) {
  var interval = el.className.match(/ms([0-9]{3,4})/);
  interval = (interval == null ? 300 : parseInt(interval[1]));
  var blink = function() {
    if (el.style.visibility == "visible") {
      el.style.visibility = "hidden";
    } else {
      el.style.visibility = "visible";
    }
  }
  window.setInterval(blink, interval);
}
Blinker.prototype = new Object();
Blinker.prototype.constructor = Blinker;