function doBlink() {
  var blink = document.all.tags("blink")
  for (var i=0; i < blink.length; i++)
    blink[i].style.visibility = blink[i].style.visibility == "" ? "hidden" : "" 
}

function startBlink() {
  if (document.all)
    setInterval("doBlink()", 1800)
}