function blinker() {
  for(i=0; i<document.getElementsByTagName("span").length; i++) {
    if(document.getElementsByTagName("span")[i].style.visibility != "hidden") {
      if(document.getElementsByTagName("span")[i].className.substr(0, 5) == "blink") document.getElementsByTagName("span")[i].style.visibility = "hidden";
    } else {
      if(document.getElementsByTagName("span")[i].className.substr(0, 5) == "blink") document.getElementsByTagName("span")[i].style.visibility = "visible";
    }
  }
  var zeit = 600;
  window.setTimeout("blinker()", zeit);
}